Introduction:


On 15 January 2026, the Paris Court of Appeal (Cour d’appel de Paris, Pôle 5 – Chambre 16) issued a decision annulling a partial arbitral award rendered under the auspices of the Permanent Court of Arbitration (PCA, Case No. 2019-34). The dispute involves the expropriation of Crimean real estate assets following Russia’s occupation of Crimea and raises crucial questions about arbitral tribunal constitution and arbitrator impartiality. This post outlines the detailed factual background and analyses the main legal issues at stake, based strictly on the reasoning of the court. The decision does not seem to be published on the website of the CoA yet, but others have shared it on social media.

Factual Background

1. The Genesis of the Dispute:

  • The dispute originated from the transfer of prominent real estate assets (Parkovoye and Koreïz) on Crimea’s southern coast, previously acquired by Ukrainian businessman Mr Rinat Akhmetov through several companies, including Investio LLC.
  • After the annexation of Crimea by the Russian Federation on 18 March 2014, administrative and judicial proceedings ultimately resulted in the transfer of these assets to the Russian state.

2. Initiation of Arbitration:

  • Mr Akhmetov and Investio LLC contended that their assets had been unlawfully expropriated without compensation.
  • They initiated arbitration proceedings on 25 February 2019, invoking the 1998 bilateral investment treaty (BIT) between Russia and Ukraine.

3. Formation of the Arbitral Tribunal:

  • The claimants (Akhmetov and Investio) nominated Prof. B. as arbitrator.
  • Russia declined to appoint an arbitrator, leading the PCA Secretary-General to designate Prof. A.
  • The president of the tribunal, Prof. E., was appointed through a process involving the PCA following procedures established by correspondence between parties and the institution.
  • The tribunal rendered a partial award on jurisdiction on 16 August 2022, asserting its authority to hear the dispute and dismissing Russia’s objections.

4. Annulment Proceedings:

  • Russia filed an application to annul the award, alleging irregularities in the tribunal’s constitution and the existence of circumstances casting doubt on the impartiality and independence of two arbitrators.
  • The Paris Court held oral arguments on 15 September 2025 and rendered its decision on 15 January 2026.

Key Legal Issues and Arguments

1. Regularity of Tribunal Constitution

  • Russia’s Position:
    • Russia alleged the agreed procedure for appointing the tribunal president was not properly followed.
    • Parties had agreed by correspondence to a process for ranking candidates for the president’s position. However, this process broke down when two candidates became unavailable, and claimants purported to withdraw from the arrangement, reverting to the default UNCITRAL rules. Russia claimed such unilateral withdrawal was impermissible, as the agreement could not be revoked by one side alone.
  • Claimants’ Position:
    • Akhmetov and Investio argued that the pre-agreed mechanism was exhausted once candidates on the list became unavailable and justified reverting to original procedures under UNCITRAL Arbitration Rules.
  • Court’s Assessment:
    • The court found that an agreement to use a party ranking process existed and was acknowledged by all in writing.
    • It further held that claimants could not unilaterally revoke that agreement and described it as binding under the relevant provisions of the UNCITRAL Arbitration Rules.
    • Because the procedure was not respected, the appointment of the tribunal president was irregular, justifying the annulment of the award under Article 1520(2º) of the French Code of Civil Procedure.

2. Impartiality and Independence of Arbitrators

  • Russia’s Allegations:
    • Raised multiple circumstances allegedly undermining the arbitrators’ impartiality, including:
      • Social media “likes” by Prof. E. approving anti-Russian opinions and public support of a Ukrainian diplomat;
      • A public statement by his law firm (O.) denouncing the Russian invasion and suspending work for Russian state entities;
      • Academic associations and online comments by Prof. B. perceived as hostile to Russia;
      • Tone and expressions in post-award correspondence deemed excessively adversarial.
  • Defence Arguments:
    • Claimants countered that:
      • These circumstances either emerged after the award or were too trivial and indirect to justify a finding of bias;
      • In some cases, such as institutional positions (O. and University of G. statements), the arbitrators could not be personally implicated;
      • Jurisprudence indicates that academic or social media conduct or law firm policy does not automatically create conflicts of interest.
  • Admissibility:
    • The court scrutinized whether Russia had raised its objections in a timely manner pursuant to UNCITRAL rules and Article 1466 CPC (which prohibits late objections without justification).
    • It concluded that there was no evidence of undue delay or strategic forbearance by Russia, thus all objections were declared admissible.
  • Substance:
    • Regarding Prof. B., the court found no reasonable doubt as to his impartiality or independence, relying on precedent for academic freedom and indirect institutional ties.
    • For Prof. E., however, the court found the combination of the firms public statement (made while the arbitration proceedings were ongoing and directly relevant to the dispute), followed by the arbitrator’s own public actions (e.g., social media endorsements), was sufficient to create a reasonable appearance of bias, particularly given the substance and timing of those positions vis-à-vis the parties’ core dispute.

Outcome of the Decision

  • The Paris Court of Appeal annulled the partial award on the following grounds:
    1. The irregular constitution of the arbitral tribunal, specifically the president’s appointment in breach of a binding party agreement.
    2. The existence of reasonable doubts as to the independence and impartiality of the tribunal president, Prof. E, arising from his law firm’s public stance during ongoing proceedings and his subsequent conduct.
  • The remaining allegations and issues were dismissed as moot.
  • Mr Akhmetov and Investio LLC were ordered to bear the costs of the annulment proceedings and to pay Russia EUR 150,000 under Article 700 CPC.

Conclusion

This case concerned an investor-state dispute involving the Russian Federation and – as the court held – the policy statement of the lawfirm and the “likes” of arbitrator Prof. E. were directly related to Russia’s war against Ukraine. As the court held, at least some of the “likes” were made even when the arbitration was already pending. In this respect, the perception of bias seems well founded.

Arbitrators need to be very careful with their interactions and public statements on social media. In this case, the Russian Federation was a party to the proceedings, but the same argument is frequently raised by Russian state-owned companies and even private Russian companies. Sofar, courts have been reluctant to confirm bias due to Social Media likes and general policy statements of firms or universities. In the light of above decision by the Paris CoA, arbitrators acting in sensible matters involving Russian parties have to be even more cautious.