Matthieu Gregoire

Professional practice

Matthieu specialises in commercial litigation, international commercial arbitration, and investor-state arbitrations. He is recommended in Chambers and Partners and/or the Legal 500 as a leading junior in (1) international arbitration, (2) public international law, (3) commercial litigation and (4) fraud. 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. Since 2015, he has been Adjunct Professor of International Commercial Arbitration at Pepperdine University and was appointed to the Attorney General’s PIL C Panel in 2017.

What Others Say

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 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 also appears in arbitration-related proceedings.

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 combines his practice with the role of adjunct professor of law (international commercial arbitration) at Pepperdine Law School, University of Malibu (London Campus). He publishes widely in the area and regularly contributes to conferences or talks.

Featured international arbitration cases include:

LCIA Arbitration (2023-ongoing): acting for a commodities trader in a dispute over the delivery of product (details not public);
ICC Arbitration (2023): acting for a respondent state-owned entity under the ICC emergency arbitrator procedure (details not public);
LCIA Arbitration (2023-ongoing): acting for the respondent in a dispute over a joint venture in the Middle East (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-ongoing): 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);
A v B (2022): acting as sole counsel for a West African State in proceedings before the Commercial Court arising out of an arbitral award rendered against it;
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 (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 Arbitration (2021): Acting for the Respondent in an ICC arbitration arising out of the largest petrochemicals plant in the world (details not public);
OIC Arbitration (2021-2022): Acting for the Claimants in an OIC Investment Agreement arbitration against a middle-eastern state (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).
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).
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 Final Award, the tribunal ordered Poland to pay c. €176 million in damages and €3.5 million in costs.
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).
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.
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).
Arbitration Challenge – Confidential; Advising a party in potential challenge proceedings following a bilateral investment treaty arbitration award (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).
Arbitration Challenge – Confidential; Advising a multinational company on enforcement proceedings in various jurisdictions following a successful £8 million ad hoc award (confidential).

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:

Claimants set out in Schedule 1 v Spence, Kewley & Others: acting for the Claimants in a claim against various individuals arising out of an alleged fraud in the property investment sector (led by Dan Saoul KC), in which a worldwide freezing order was obtained, and involving numerous hearings before the Commercial Court and a hearing before the Court of Appeal [2022] EWCA Civ 500 clarifying the law on fortification of cross-undertakings.
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. 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:

Claimants set out in Schedule 1 v Spence, Kewley & Others: acting for the Claimants in a claim against various individuals arising out of an alleged fraud in the property investment sector (led by Dan Saoul KC), involving numerous hearings before the Commercial Court and a hearing before the Court of Appeal [2022] EWCA Civ 500 clarifying the law on fortification of cross-undertakings.
Reditum v (1) Mr Kooner and (2) Aston Martin Works: successfully acting as sole counsel for Aston Martin Works in proceedings in the Chancery Division arising out of the financing of high-end Aston Martins.
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); Acting 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); Acting for the defendants in a claim arising out of financing agreements for wind farm projects.
Reditum SPV 2 Ltd v Kooner & Others (Business List, Chd, 2020); Acting for Aston Martin Works Limited in a claim arising out of the financing of a high-end car.
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.
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 – Joint Venture Dispute; Acting for the Respondent in an LCIA Arbitration arising out of a joint venture in a CIS State (details not public).
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.
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).
ICC Case – Telecommunications Sector in Ukraine; Acting as sole counsel 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).
LCIA Arbitration – Transport of Ethyl Contract; Acting as sole counsel in an LCIA arbitration arising out of the transport of ethyl (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).
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.

Matthieu was appointed to the Attorney General’s Public International Law C Panel of Counsel in 2017.

Featured cases include:

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 No. 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).
ICSID Arbitration; Acting for a South Asian State in a claim brought by investors arising out of a renewable power plant project.
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 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 Final Award, the tribunal ordered Poland to pay c. €176 million in damages and €3.5 million in costs.
Matthieu was part of the counsel team which successfully acted for PL Holdings, together with Fietta LLP (Stephen Fietta, Ashique Rahman, Laura Rees-Evans and Sarah Macrory), Linklaters (Matthew Weiniger QC, Ula Cartwright-Finch, Cezary Wisniewski and Alicja Zielinska-Eisen), and Sean Aughey.
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.
ICSID Case No. ARB/14/9 – City-State N.V. et al. v Ukraine; Acting for the claimants in City-State N.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.
Arbitration Challenge – Confidential; Advising a party in potential challenge proceedings following a bilateral investment treaty arbitration award (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 QC and Graham Dunning QC).