Matthieu Gregoire

Professional practice

Matthieu specialises in commercial litigation, international commercial arbitration, and investor- state arbitrations. He has particular expertise and is recommended in Chambers and Partners and/or the Legal 500 as a leading junior in:

International Arbitration: “Matthieu is among the best counsel of his generation. Very hard-working, brilliant advocacy skills and extremely responsive”; “A very effective cross-examiner”; “He’s capable of very quickly assimilating vast amounts of information and considering complex legal and commercial issues and providing clear, decisive advice”; “A strategic thinker, very commercial, a great advocate who is very calm and articulate, and has the ear of the tribunal, very user-friendly. Definitely one of the best of his generation.”
Commercial Litigation: “One of the best senior juniors on the market”; “His attention to detail and teamwork is exceptional.”
Commercial Fraud: “ He is very tactically aware and his attention to detail and ability to marshall vast amounts of material is second to none – a huge asset in a fraud case”
Public International Law. “He’s a genuine star in the making.” “Matthieu is very clever and extremely hard-working.” ““He is absolutely excellent on his feet, and the great thing about him is that he can act and plead in English and French. He’s super reliable, very smart and client-friendly.”

He was a nominee in the Legal 500 Bar Awards for International Arbitration Junior of the Year 2022 and again for the Year 2023.

Matthieu has acted for governments, corporations and individuals in oil and gas, renewable energy, mining, manufacturing, joint venture and finance disputes. Many of these have included issues of civil fraud. Matthieu’s experience includes the following:

Acting and/or advising in matters before all levels of English courts, in commercial and international disputes.
Acting and/or advising in numerous investment treaty arbitrations pursuant to a wide array of investment treaties with issues relating to most major legal sectors, with extensive experience of ICSID, SCC, UNCITRAL and ad hoc rules.
Acting and/or advising in numerous commercial arbitrations, with experience of ad-hoc and institutional rules (ICC, LCIA, SCC, UNCITRAL), across a range of sectors and industries. Many of which included issues relating to a variety of international governing laws.
Advising States, non-governmental organisations, private commercial entities and private individuals on a diversity of commercial, arbitration and public international law issues, including treaty interpretation, WTO/Trade law, and implications of Brexit.

Matthieu graduated from the University of Cambridge in 2008, completed his masters at Sciences Po Paris in 2010 and his LLM at Georgetown, D.C in 2010. He was called to the New York Bar in 2011 during his time at an international law firm in Paris before being called to the Bar in England and Wales in 2013.

What Others Say

Chambers and Partners: International Arbitration: 2024/2025: “He is extremely capable in a technical sense, but he’s also able to interact with clients, since he used to be a solicitor.” “Matthieu is one of the best senior juniors in the London market and beyond.” “He’s capable of very quickly assimilating vast amounts of information and considering complex legal and commercial issues and providing clear, decisive advice.” “Matthieu is a rising star in this field.”
Chambers & Partners Public International Law: 2024/2025: “Matthieu is extremely capable in a technical sense, but he’s also good with clients because he has experience as a solicitor.” “He’s a genuine star in the making.” “Matthieu is very clever and extremely hard-working.”
Legal 500: Commercial Litigation: 2024/2025: “One of the best senior juniors on the market. Fully bilingual and a great pleasure to work with.”
Legal 500: International Arbitration: 2024/2025: “A strategic thinker, very commercial, a great advocate who is very calm and articulate, and has the ear of the tribunal, very user-friendly. Definitely one of the best of his generation.”
Legal 500: Fraud: Civil: 2024/2025: “He is very tactically aware and his attention to detail and ability to marshall vast amounts of material is second to none – a huge asset in a fraud case.”
Chambers & Partners Public International Law: 2023/2024: “Matthieu is very clever and extremely hard-working.”
Chambers and Partners: International Arbitration: 2023/2024: “To me, he is definitely one of the rising stars of the Bar.” “He is extremely likeable; he brings a bit of French flair to the cases. The clients hold him in the highest regard.”
Legal 500: International Arbitration: 2023/2024: “Matthieu is among the best counsel of his generation. Very hard-working, brilliant advocacy skills and extremely responsive. Moreover, he’s very commercially-minded and great with clients. A very effective cross-examiner.”
Chambers & Partners Public International Law: 2022/2023: “He is absolutely excellent on his feet, and the great thing about him is that he can act and plead in English and French. He’s super reliable, very smart and client-friendly.” “He’s very bright, on top of the detail and can see the bigger picture.” “He is excellent, can act and plead in English and French, is excellent on his feet and is very reliable.” “Matthieu is very approachable, engaged and personable. He has a great ability to make the most complex issues look simple.”
Legal 500: Commercial Litigation: 2022/2023: “His attention to detail and teamwork is exceptional.”
Legal 500: international arbitration: 2022/2023: “… excellent in his analytical rigour, leaving no stone unturned. He is also a natural advocate who can tickle tribunal’s judgment bones easily.’
Legal 500: public international Law: 2022/2023: “… a fantastic bilingual (English & French) lawyer with strong technical skills and business acumen. He is very good at identifying strengths and weaknesses in a case.”
Chambers and Partners: International Arbitration: 2021/2022: “He has an extraordinary legal mind and he has excelled in advocacy. Technically he is very sound, and he understands the legal principles that apply and applies them in a way that is compelling.”
Chambers and Partners: public international law: 2021/2022: “He’s an incisive, reliably hard-working barrister who was a solicitor for a number of years in France.” “He’s bilingual and has the ability to handle proceedings both in English and French.”
Legal 500: international arbitration: 2021/2022: “Knowledgeable and personable. He is easy to work with and can work seamlessly across various co-counselling arrangements. Being fluent in French gives him a further edge over his colleagues.”
Legal 500: public international law: 2021/2022: “An absolutely fantastic advocate – responsive, accessible and a corner stone of any team.”
Who’s Who UK Bar 2020: arbitration: “a strong and measured advocate” with “a magnificent mind”; “Matt has excellent judgment and cuts through to the essence of any issue”.
Who’s Who Global 2020-2023: “future leader” in international arbitration.

ARBITRATION-RELATED COURT APPLICATIONS

Matthieu has extensive experience of arbitration-related court applications, and notable (a) challenges; (b) injunctive relief.

Challenges

A v B (Commercial Court, 2025): acting for the respondent in a s.67 challenge in respect of an award rendered under the ICC rules in 2024.
A v B (Commercial Court, 2024-2025): acting for an investor in a s.67 challenge in respect of award rendered under a BIT.
Czech Republic v (1) Diag Human SE; (2) Josef Stava [2024] EWHC 503 (Comm); [2024] Bus LR 929 : acted for the Czech Republic (led by Lucas Bastin KC, with Peter Webster and Katherine Ratcliffe) in a challenge under s.67 and 68 of the Arbitration Act 1996 to an arbitral award dated 18 May 2022 in which over Euro 336 million was awarded by the claimants against the Czech Republic..
A v B (Commercial Court, 2023): acted for the financial services branch of an American global food corporation in resisting the challenge of an arbitral award rendered in its favour for USD 124 million. Successfully obtained a security for costs, which led to the discontinuance of the challenge. (unled, instructed by A&O Shearman).
Eurafric v Government of Nigeria and others [2022] EWHC 3548 – Matthieu was instructed as sole counsel on behalf of the Government of Nigeria to seek the variation of the order of Mr Justice Popplewell dated 15 January 2018 registering an arbitral award.
Micula & Others v Romania [2017] EWHC 31 (Comm); Acting as junior counsel for the First Claimant in the enforcement proceedings arising out of the Award in Micula & Others v Romania [2017] EWHC 31 (Comm) (led by Sir Alan Dashwood KC and Patrick Green KC).
Arbitration Challenge – Confidential; Advising a party in potential challenge proceedings following a bilateral investment treaty arbitration award (details not public).
Arbitration Challenge – Confidential; Advising a multinational company on enforcement proceedings in various jurisdictions following a successful £8 million ad hoc award (confidential).

Injunctive Relief (including anti-suit injunctions and freezing orders)

Commerzbank v RusChem [2024] EWHC 1474 (Comm) (led by Paul McGrath KC and then Richard Millett KC, instructed by A&O Shearman): successfully obtained ex parte injunctive relief ([2023] EWHC 2510 (Comm) ) and then final anti-suit, anti-anti-suit and anti-enforcement injunctions against a Russian Bank, before successfully obtaining its revocation following a change of circumstances in Russia ([2025] EWHC 924 (Comm)).
Investcom v PLC [2024] EWHC 2505 (Comm), [2024] Bus LR 1764: obtained injunctive relief in respect of one set of proceedings issued in Liberia, on the ground that it was brought in breach of an arbitration agreement and/or was vexatious and oppressive (led by Stephen Houseman KC, instructed by Skaddens).
SFC Finance Limited v Ketan and Chetan Kotecha: obtained ex parte WFO and final injunctive relief at a return date in respect of an ongoing ICC arbitration
Cupreus v Whiteshell [2023] EWHC 3449 (Comm): obtained an anti-suit injunction on an ex parte basis, which was maintained on the return date, in respect of proceedings brought by related third parties to the arbitration agreement (unled, instructed by Pinsent Masons LLP)

COMMERCIAL AND INVESTOR-STATE ARBITRATION

Matthieu practices investment treaty arbitration and international commercial arbitration, often in proceedings with an English law element (whether as the governing law of the contract or the proceedings), either led or often as sole counsel. Matthieu approaches his arbitration work in a collaborative way with those instructing him. He also appears in arbitration-related proceedings (on which, see below). Matthieu has particular familiarity with claims involving States and state-owned entities.

Matthieu has built on his experience as an attorney in the Paris office of Cleary Gottlieb, Steen & Hamilton, where he acted in investment treaty and commercial arbitrations, and as a consultant for the World Bank, where he advised States and Chambers of Commerce on the creation of arbitration and/or mediation laws or centres and the reform of investment law.

Matthieu has also taught international commercial arbitration at Pepperdine Law School, University of Malibu (London Campus) and published widely in the area. He regularly contributes to conferences or talks.

Commercial Arbitrations

ICC (2024-2025): Acting for a respondent State in an ICC arbitration said to be worth USD 500 million arising out of an energy project (including cross-examination of key factual witness and quantum expert witnesses). Successfully defeating entire claim with all costs awarded in favour of the Respondent.
PCA Case (2025): Acting for a respondent state in a dispute in relation to a guarantee (details not public);
LCIA Arbitration (2023-2024): Acting for a commodities trader in a dispute over the delivery of product (details not public);
ICC Emergency Arbitration (2023): Acting for a respondent state-owned energy company under the ICC emergency arbitrator procedure (details not public);
LCIA Arbitration (2023-2024): Acting for a leading international logistics company in LCIA proceedings arising out a joint venture in the Middle East. The case involved allegations of fraud and conspiracy (details not public);
A v B (2023): Acting as sole counsel for a global food corporation in successfully obtaining the dismissal of a challenge to an arbitral award (details not public);
UNCITRAL Arbitration (2022-2024): Acting for the Respondent state-owned West African electricity company in a claim said to be worth USD 100 million arising out of an energy project (including cross-examination of fact, technical and quantum expert witnesses) (details not public);
LCIA Arbitration (2021): Acting on behalf of an insurer in a dispute arising out of a commodities project in Southern Africa. The case involved allegations of fraud and was said to be worth over USD 40 million (details not public);
ICC Case (2021): Matthieu was instructed by a consortium of three Parisian firms to deal with the English law aspects of an arbitration arising out of a joint venture for the development of a hydrocarbon facility in a central African State.
ICC Arbitration (2021): Acting for the Respondent in an ICC arbitration arising out of the largest petrochemicals plant in the world (details not public);
ICC Arbitration (2020): Acting for the Respondent in an ICC arbitration said to be worth over USD $500 million arising out of a tolling agreement relating to a liquified natural gas plant project in the Middle East (details not public);
LCIA Arbitration (2018-2019) – Investor vs East African State; Acting for a Claimant in an LCIA Arbitration arising out of an energy project in an East African State (details not public).
LCIA Arbitration (2017) – Joint Venture Dispute; Acting for the Respondent in an LCIA Arbitration arising out of a joint venture in a CIS State involving jurisdiction issues, alleged minority oppression and questions of interpretation of the joint venture agreement.
ICC Arbitration (2017) – West African Construction Project; Acting for the Respondent in an ICC Arbitration arising out of an infrastructure project in West Africa (details not public).
ICC Arbitration (2016) (Telecoms): Acting as junior counsel for a national telecommunications operator in a substantial ICC arbitration (foreign law).
LCIA Arbitration (2016) – Sale of Fuel Alcohol Contract; Acting as sole counsel in an LCIA arbitration arising out of the sale of fuel alcohol (details not public).
LCIA Arbitration (2016) – Transport of Ethyl Contract; Acting as sole counsel in an LCIA arbitration arising out of the transport of ethyl alcohol (details not public).
ICC Case (2016) – Telecommunications Sector in Ukraine; Acting as sole counsel in a two- week hearing for a Ukrainian company in a commercial arbitration pursuant to the ICC Rules in relation to a dispute under a contract in the telecommunications sector (details not public).

Investor-State Arbitrations

Investor v State (2025): acting for an investor in a claim against a State arising out of sanctions
Pathfinder Minerals v Mozambique ICSID Case No. ARB/24/4: acting for an investor in a claim against a State arising out of a mining project
Skubenko and others v North Macedonia, ICSID Case No. Arb/19/9; Acting for the Claimants in Skubenko and others v North Macedonia, ICSID Case Arb/19/9, in a dispute over a copper mining complex in North Macedonia, under the Ukraine-North Macedonia BIT; Al-Tuwairqi v Pakistan (UNCITRAL); Acting for the Claimants in Al-Tuwairqi v Pakistan, a dispute over a steel manufacturing plant in Karachi, under the OIC Investment Treaty (under the UNCITRAL Rules);
KLS Energy Lanka Sdn. Bhd v. Sri Lanka ICSID Case No. ARB/18/13: Acting for a South Asian State in a claim brought by investors arising out of a renewable power plant;
OIC Arbitration (2021-2022): Acting for the Claimants in an OIC Investment Agreement arbitration against a middle-eastern state (details not public);
SCC Arbitration – PL Holdings v Poland (Luxembourg-Poland BIT); Matthieu acted for PL Holdings, a Luxembourg company, which prevailed in its SCC arbitration against the Republic of Poland. The claim concerned the uncompensated expropriation of our client’s equity investment in a Polish bank, in violation of the Luxembourg-Poland BIT. In its recent Award, the tribunal ordered Poland to pay c. €176 million in damages and €3.5 million in costs.
SCC Arbitration – Investor v State (ECT); Acting for the Claimant in arbitration commenced under the ECT and governed by the SCC rules in the energy sector in relation to breaches by an Eastern European State of the ECT (details not public).
ICSID Case No. ARB/14/9 – City-State N.V. et al. v Ukraine; Acting for the claimants in City-State V. et al. v Ukraine, ICSID Case No. ARB/14/9, a dispute under a bilateral investment treaty in relation to various breaches of the treaty.
ICSID Case No. ARB/12/1 – Tethyan Copper Company Pty Limited v Islamic Republic of Pakistan; Acting for the Respondent in Tethyan Copper Company Pty Limited v Islamic Republic of Pakistan, ICSID Case No. ARB/12/1, a dispute under a bilateral investment treaty, in relation to the refusal of a mining licence over very large-scale copper and gold deposits at Reko Diq, in Pakistan (led by Cherie Blair KC and Graham Dunning KC).

Civil fraud & asset recovery

Many of Matthieu’s cases, whether before arbitral tribunals or English Courts, involve allegations of civil fraud. Matthieu has extensive experience of worldwide freezing orders, asset disclosure and other forms of injunctive relief in support of such proceedings. He also has extensive experience of allegations of corruption and civil fraud made in international arbitrations, including investment-treaty arbitrations.

Featured English Court cases include (the arbitration cases are set out above):

The Bourlakova v Bourlakov litigation: acting for a number of Panamanian corporate defendant in Chancery Court proceedings, part of a multi-jurisdictional dispute concerning assets worth in excess of US$1 billion (led by Graham Dunning KC, with Ellen Tims).
4VVV Limited and Others v Spence, Kewley & Others (Commercial Court – ongoing): acting for the Claimants in a claim against various individuals arising out of a fraud in the property investment sector (led by Dan Saoul KC). The claim has given rise to multiple hearing and judgments, including (1) An 8-week trial before Mr Justice Foxton in respect of 10 Lead Claimants, who succeeded in their claims for deceit and unlawful means conspiracy, and in seeking determinations that the investment schemes in question amounted to unregulated collective investment schemes and were therefore subject to the Financial Services and Markets Act 2000, and related regulations (“FSMA”): [2024] EWHC 2434 (Comm); (2) Obtaining a worldwide freezing order and multiple ancillary orders. A hearing before the Court of Appeal [2022] EWCA Civ 500 clarified the law on fortification of cross-undertakings and the WFO was maintained following a 3-day hearing before HHJ Pelling KC [2023] EWHC 1; (3) Resisting an attempt to apply the indemnity principle to evade the payment of indemnity costs orders against the Defendants: [2024] EWHC 3035 (Comm)
Amjad Rihan v Ernst & Young Global Limited & Others [2020] EWHC 901 (QB); Acting for Amjad Rihan, the successful claimant, in proceedings brought against EY entities (led by Ben Hubble KC) (one of The Lawyer’s Top 20 Cases of 2020).
LICT & Others v VTB Capital Plc & Others [2019] EWHC 1747 (Comm); Successfully acting for a Bulgarian telecommunications company, Viva Telecom, in the Commercial Court in a claim brought by VTB Bank Plc involving allegations of fraud and conspiracy, in a claim said to be worth over £200 million (led by Graham Chapman KC).
Al Rushaid Petroleum Investment Company (2) Al Rushaid Parker Drilling Company Limited v John Bradnam (2) JB Cons (2003) Limited (3) JB Management Limited (4) John Bradnam (trading as JB Consulting) [2017] EWHC 2573; Acting as junior to Justin Fenwick KC in civil fraud claim.

Commercial dispute resolution

Matthieu represents clients in commercial disputes including those concerning business investments, the sale and supply of goods and services, complex civil fraud, as well as claims raising issues of conflicts of laws or international enforcement both before the English Courts and arbitral tribunals (on which, see above). Matthieu regularly appears in the Commercial Court, both led and unled, and has extensive experience of acting both led and unled before international tribunals.

Representative examples include:

The Bourlakova v Bourlakov litigation: acting for a number of Panamanian corporate defendant in Chancery Court proceedings, part of a multi-jurisdictional dispute concerning assets worth in excess of US$1 billion (led by Graham Dunning KC, with Ellen Tims).
Banco de Sabadell v Cerberus Global NPL Associates, LLC & Ors [2024] EWHC 3022 (Comm): acting for the Claimant (led by James Collins KC, with Akash Sonecha) in proceedings worth over €400 million relating to Spanish law governed investment agreements concluded between Banco de Sabadell, one of the major Spanish retail banks, and entities within the Cerberus group in July 2018 and August 2019 for the purchase of portfolios of Spanish real estate owned assets. Following a week-long trial, Mr Justice Andrew Baker rejected the Defendant’s arguments that payment was subject to reaching registration thresholds and granted the Claimant’s claim in full (together with indemnity costs).
4VVV Limited and Others v Spence, Kewley & Others (Commercial Court – ongoing): acting for the Claimants in a claim against various individuals arising out of a fraud in the property investment sector (led by Dan Saoul KC). The claim has given rise to multiple hearing and judgments, including (1) An 8-week trial before Mr Justice Foxton in respect of 10 Lead Claimants, who succeeded in their claims for deceit and unlawful means conspiracy, and in seeking determinations that the investment schemes in question amounted to unregulated collective investment schemes and were therefore subject to the Financial Services and Markets Act 2000, and related regulations (“FSMA”): [2024] EWHC 2434 (Comm); (2) Obtaining a worldwide freezing order and multiple ancillary orders. A hearing before the Court of Appeal [2022] EWCA Civ 500 clarified the law on fortification of cross-undertakings and the WFO was maintained following a 3-day hearing before HHJ Pelling KC [2023] EWHC 1; (3) Resisting an attempt to apply the indemnity principle to evade the payment of indemnity costs orders against the Defendants: [2024] EWHC 3035 (Comm)
Município de Mariana v BHP: acted the claimants in relation to anti-suit relief mattersin a particularly large-scale and high-value group action (c. £36 billion claimed on behalf of over 700,000 claimants) for damages related to an environmental disaster caused by the collapse of a dam (led by Daniel Oudkerk KC and with Stephen Donnelly, instructed by Pogust Goodhead)
Viarentis & Vectryss v Viagefi and Others [2023] EWHC 3316 (KB): acting (unled) for the defendant funds in defeating the majority of the claims brought by the Claimants in respect of investment schemes in the South of France, following a 5-day trial in July 2023. Further hearings on matters consequent on the judgment took place in 2024: [2024] EWHC 2662 (KB); [2024] EWHC 166 (KB)
Reditum v (1) Mr Kooner and (2) Aston Martin Works: successfully acted as sole counsel for Aston Martin Works in proceedings in the Chancery Division arising out of the financing of high-end Aston Martins. Mr Kooner’s claim against Aston Martin was defeated following a 4-day trial before Master Pester.
Amjad Rihan v Ernst & Young Global Limited & Others [2020] EWHC 901 (QB); Acting for Amjad Rihan, the successful claimant, in proceedings brought against EY entities (led by Ben Hubble KC) (one of The Lawyer’s Top 20 Cases of 2020).
PPRS v Tecar (Comm Court, 2020): acted for the claimant in a Commercial Court claim arising out of an SPA of a paper business in Romania.
Alte Liebe 1 Limited & Another v Windpark Fonds & Another (Comm Court, 2020); Acted for the defendants in a claim arising out of financing agreements for wind farm projects.
LICT & Others v VTB Capital Plc & Others [2019] EWHC 1747 (Comm); Successfully acting for a Bulgarian telecommunications company, Viva Telecom, in the Commercial Court in a claim brought by VTB Bank Plc involving allegations of fraud and conspiracy, in a claim said to be worth over £200 million (led by Graham Chapman KC).
Al Rushaid Petroleum Investment Company (2) Al Rushaid Parker Drilling Company Limited v John Bradnam (2) JB Cons (2003) Limited (3) JB Management Limited (4) John Bradnam (trading as JB Consulting) [2017] EWHC 2573; Acting as junior to Justin Fenwick KC in civil fraud claim.
Ethiopian Airlines v Honeywell & Others (commercial court); Acting as junior for Part 20 Defendant in a multi-million pound claim relating to a lithium battery fire on new a Boeing 787 Dreamliner at London Heathrow.
Chevron Corporation v Amazonia Recovery Limited & others (Supreme Court, Gibraltar); Acting as junior counsel for a Defendant in Chevron Corporation v Amazonia Recovery Limited & others (Supreme Court, Gibraltar), complex proceedings concerning alleged commercial conspiracy arising from US$18 billion judgment in respect of environmental pollution in Ecuador with associated arbitration proceedings (the Chevron v Ecuador BIT proceedings) and proceedings in New York and elsewhere (led by Vernon Flynn KC (Essex Court Chambers), Patrick Green KC (Henderson Chambers) and Jonathan Adkin KC (Serle Court) and Henry Warwick).

Energy & natural resources

Many of the matters Matthieu handles are related to the energy and natural resources sector. Matthieu’s experience includes cases arising out of tolling agreements, oil and gas production and supply, electricity generation and geothermal technology. Matthieu also has experience of disputes arising out of solar and wind energy generation and has a particular interest in renewable energies. His experience of natural resources includes copper and gold mining disputes. Matthieu also has experience of disputes involving heavy industry.

Notable cases include:

LCIA Arbitration: acting on behalf of an insurer in a dispute arising out of a commodities project in Southern Africa. The case involved allegations of fraud and was said to be worth over USD 40 million.
A v B: acting as sole counsel for a West African State in proceedings before the Commercial Court arising out of an arbitral award rendered against it;
UNCITRAL Arbitration – Acting for the Respondent state-owned West African electricity company in a claim said to be worth USD 100 million arising out of an energy project;
ICC Arbitration – Acting for the Respondent in an ICC arbitration said to be worth over USD $500 million arising out of a tolling agreement relating to a liquified natural gas plant project in the Middle East.
Skubenko and others v North Macedonia, ICSID Case No. Arb/19/9 – Acting for the Claimants in Skubenko and others v North Macedonia, ICSID Case Arb/19/9, in a dispute over a copper mining complex in North Macedonia, under the Ukraine-North Macedonia BIT.
Al-Tuwairqi v Pakistan (UNCITRAL); Acting for the Claimants in Al-Tuwairqi v Pakistan, a dispute over a steel manufacturing plant in Karachi, under the OIC Investment Treaty (under the UNCITRAL Rules).
KLS Energy Lanka Sdn. Bhd v. Sri Lanka ICSID Case No. ARB/18/13: Acting for a South Asian State in a claim brought by investors arising out of a renewable power plant
LCIA Arbitration – Investor vs East African State; Acting for a Claimant in an LCIA Arbitration arising out of an energy project in an East African State (details not public).
LCIA Arbitration – Sale of Fuel Alcohol Contract; Acting as sole counsel in an LCIA arbitration arising out of the sale of fuel alcohol (details not public).
LCIA Arbitration – Transport of Ethyl Contract; Acting as sole counsel in an LCIA arbitration arising out of the transport of ethyl alcohol (details not public).
SCC Arbitration – Investor v State (ECT); Acting for the Claimant in arbitration commenced under the ECT and governed by the SCC rules in the energy sector in relation to breaches by an Eastern European State of the ECT (details not public).
ICSID Case No. ARB/12/1 – Tethyan Copper Company Pty Limited v Islamic Republic of Pakistan; Acting for the Respondent in Tethyan Copper Company Pty Limited v Islamic Republic of Pakistan, ICSID Case No. ARB/12/1, a dispute under a bilateral investment treaty, in relation to the refusal of a mining licence over very large-scale copper and gold deposits at Reko Diq, in Pakistan (led by Cherie Blair KC and Graham Dunning KC).

Public international law

Matthieu practices international investment treaty arbitration and international public law, with a particular interest in international economic law. He acts for claimants and respondents in cases under a variety of rules, in particular ICSID, SCC, UNCITRAL, as well as in arbitration-related court proceedings.

Earlier in his career, Matthieu was a member of the Attorney General’s Public International Law Panel of Counsel (Panel C).

Featured cases include:

Investor v State (2025): acting for an investor in a claim against a State arising out of sanctions
Pathfinder Minerals v Mozambique ICSID Case No. ARB/24/4: acting for an investor in a claim against a State arising out of a mining project.
Czech Republic v (1) Diag Human SE; (2) Josef Stava [2024] EWHC 503 (Comm); [2024] Bus LR 929 : acted for the Czech Republic (led by Lucas Bastin KC, with Peter Webster and Katherine Ratcliffe) in a challenge under s.67 and 68 of the Arbitration Act 1996 to an arbitral award dated 18 May 2022 in which over Euro 336 million was awarded by the claimants against the Czech Republic.
Skubenko and others v North Macedonia, ICSID Case No. Arb/19/9; Acting for the Claimants in Skubenko and others v North Macedonia, ICSID Case Arb/19/9, in a dispute over a copper mining complex in North Macedonia, under the Ukraine-North Macedonia BIT; Al-Tuwairqi v Pakistan (UNCITRAL); Acting for the Claimants in Al-Tuwairqi v Pakistan, a dispute over a steel manufacturing plant in Karachi, under the OIC Investment Treaty (under the UNCITRAL Rules);
KLS Energy Lanka Sdn. Bhd v. Sri Lanka ICSID Case No. ARB/18/13: Acting for a South Asian State in a claim brought by investors arising out of a renewable power plant;
OIC Arbitration (2021-2022): Acting for the Claimants in an OIC Investment Agreement arbitration against a middle-eastern state (details not public);
SCC Arbitration – PL Holdings v Poland (Luxembourg-Poland BIT); Matthieu acted for PL Holdings, a Luxembourg company, which prevailed in its SCC arbitration against the Republic of Poland. The claim concerned the uncompensated expropriation of our client’s equity investment in a Polish bank, in violation of the Luxembourg-Poland BIT. In its recent Award, the tribunal ordered Poland to pay c. €176 million in damages and €3.5 million in costs.
SCC Arbitration – Investor v State (ECT); Acting for the Claimant in arbitration commenced under the ECT and governed by the SCC rules in the energy sector in relation to breaches by an Eastern European State of the ECT (details not public).
ICSID Case No. ARB/14/9 – City-State N.V. et al. v Ukraine; Acting for the claimants in City-State V. et al. v Ukraine, ICSID Case No. ARB/14/9, a dispute under a bilateral investment treaty in relation to various breaches of the treaty.
ICSID Case No. ARB/12/1 – Tethyan Copper Company Pty Limited v Islamic Republic of Pakistan; Acting for the Respondent in Tethyan Copper Company Pty Limited v Islamic Republic of Pakistan, ICSID Case No. ARB/12/1, a dispute under a bilateral investment treaty, in relation to the refusal of a mining licence over very large-scale copper and gold deposits at Reko Diq, in Pakistan (led by Cherie Blair KC and Graham Dunning KC).
Anderson v Turning Point Eespro [2019] EWCA Civ 815; Acting as junior counsel for the Lord Chancellor in the Court of Appeal in Anderson v Turning Point Eespro [2019] EWCA Civ 815, a civil procedure case giving rise to questions of public international law (led by Richard O’Brien).
Advice – intra-EU BIT arbitration; Matthieu has advised a number of clients in the intra-EU BITs about the consequences of the CJEU’s Achmea decision.
Micula & Others v Romania [2017] EWHC 31 (Comm); Acting as junior counsel for the First Claimant in the enforcement proceedings arising out of the Award in Micula & Others v Romania [2017] EWHC 31 (Comm) (led by Sir Alan Dashwood QC and Patrick Green QC). SCC Arbitration – PL Holdings v Poland (Luxembourg-Poland BIT); Matthieu acted for PL
R(Miller & others) v Secretary of State for Exiting the European Union [2017] UKSC 5; Acting as junior counsel for the intervening parties in R (Miller & others) v Secretary of State for Exiting the European Union [2016] EWHC 2768, and before the Supreme Court in R(Miller & others) v Secretary of State for Exiting the European Union [2017] UKSC 5 (led by Patrick Green QC and Henry Warwick).
SCC Arbitration – Investor v State (ECT); Acting for the Claimant in arbitration commenced under the ECT and governed by the SCC rules in the energy sector in relation to breaches by an Eastern European State of the ECT (details not public).
Case T-713/16 – Fair Deal for Expats & others v Commission of the European Union; Acting for the applicant in Fair Deal for Expats & others v Commission of the European Union (Case T-713/16): challenge in the General Court of the European Union under Article 263 TFEU in respect of measures preventing negotiations between representatives of the United Kingdom and the Commission pending notice under Article 50 TEU.