Xavier Nyssen

Xavier Nyssen

Xavier Nyssen


Paris | 32 rue de Monceau, Paris, France 75008
+33 1 57 57 80 01 | +33 1 57 57 80 81


Xavier Nyssen is the former head of Dechert’s international dispute resolution practice. Since 1988, he has concentrated his practice in international arbitration, specifically in the telecom, energy, pharmaceutical and arms procurement sectors.

He has acted as counsel in numerous arbitrations whether ad hoc or under the rules of the International Chamber of Commerce (ICC), the London Court for International Arbitration (LCIA) or the European Development Fund (FED). He is also well versed in proceedings on the enforcement of arbitral awards, notably when sovereigns are involved.

Mr. Nyssen regularly advises foreign companies on collecting evidence and on the annulment of arbitration awards in French proceedings. He also acts as arbitrator.

Mr. Nyssen has been consistently recognized by both Chambers Europe and Chambers Global for his "strong track record on arbitrations in the energy, pharmaceuticals and telecommunications sectors." According to The Legal 500 Parishis human qualities enable him to comprehend not only the legal challenges of a case, but all its other aspects as well”. He is listed in The Legal 500 EMEA: France and Décideurs Stratégie Finance Droit. Sources described him as a client-oriented, technically gifted and creative practitioner who provides "very high-level advice on complex matters." In 2017 and 2018, he was listed as a leading lawyer by Who's Who Legal: Arbitration.

Before joining Dechert in 2005, he worked in New York and Brussels and served as co-managing partner of the Paris office of another international law firm, where he was responsible for the Litigation department.

  • A leading European telecom company in a shareholders’ dispute exceeding US$1.5 billion. 
  • An Asian state entity in connection with a US$2 billion dispute arising from a military procurement contract and the payment of illicit commissions. 
  • A leading company in an ICC arbitration against an Asian state. 
  • A leading satellite operator in a dispute arising from a coordination agreement. 
  • A private equity house in a post-acquisition dispute under the rules of the German Institute of Arbitration. 
  • A major U.S. oil company in a dispute against a West African state involving a production sharing agreement. 
  • An Italian construction group in an ICC arbitration against a Spanish contractor. 
  • A major energy company in a shareholders’ dispute. 
  • University of Liège, M.A., 1986
  • Columbia Law School, LL.M., 1999
  • Paris, 1993
  • Brussels, 1992
  • New York, 2002
  • French
  • English
  • Advisory Board, Institute for Transnational Arbitration
  • Belgian Center for Mediation and Arbitration (CEPANI)
Speaking Engagements
  • Business & Legal Forum Conference, Paris (October 17, 2019)
  • ICC Africa Arbitration Conference — Lagos (June 19, 2018)
  • Droit de l'Arbitrage International en Iran — Comparative Legislation Society, Paris (February 5, 2018)
  • Interim Measures and Emergency Arbitration proceedings (“EA proceedings”) in construction disputes — ICC conference - Dispute Resolution and Construction Contracts in Egypt, Cairo (November 19, 2017)
  • La relation d'affaires à l'épreuve du risque contentieux. Comment la sauvegarder ? — Business & Legal Forum, Paris (October 12, 2017)
  • Investor – State disputes in Africa – State Parties and the arbitral process – where do they get it wrong? — 2nd ICC Africa Regional Arbitration Conference, Lagos (May 14, 2017)
  • Transparence et confidentialité : les défis de l'arbitrage — Les rencontres de l'Arbitrage et du Contentieux, Paris (February 4, 2016)
  • Applicable law and dispute resolution in contracts — AFJE - Association Francaise des Juristes d'Entreprise, Paris (October 16, 2015)
  • Management des litiges ou comment réduire une perte économique — Business & Legal Forum, Paris (September 8, 2015)
  • Les Rencontres de l'Arbitrage et du Contentieux - Arbitrage & médiation : des procédures matures et maitrisables ? — Organised by Option Finance, Paris (January 29, 2015)
  • Litige : comment le résoudre sans rompre la relation d'affaires, gagner en efficacité et réduire les coûts ? — Business & Legal Forum, Paris (October 9, 2014)
  • Shareholders Dispute - Case Study Under the Patronage of Dechert LLP — Dispute Resolution in M&A Transactions: Tactics, Challenges, Defences, Warsaw (June 6, 2013)
  • Arbitration - What are the Options? — Korean In-House Counsel Forum, Seoul (March 30, 2010)
  • Bilgi University Arbitration Day — Akinci Law Firm Seminar, Istanbul (October 24, 2008)