Quentin Declève focuses on international litigation and arbitration, as well as on EU and national competition law and international trade law. He also represents clients before the EU Courts and before Belgian civil and commercial courts.

Quentin has been involved in key cases relating to restrictive measures and sanctions taken against individuals and against sovereign States by the European Union and the United Nations (Cases T-375/14 to T-378/14 on measures adopted by the European Union with regard to Egyptian citizens). Quentin also coordinates the defence of the Belgian State in disputes involving the sanctions adopted by the UN Security Council and the European Union against Libya.

Quentin also assists clients in the field of competition law, merger control and State aids both in administrative and court proceedings. In particular, he intervened in the procedure to annul the Decision of the European Commission concerning State aid implemented by Belgium in favour of the Duferco group.

Quentin also advised the Republic of Benin in discussions within Working Group III of the United Nations Commission on International Trade Law to reform investor-state dispute settlement mechanisms.

From 2013 to 2015, Quentin worked part-time as a teaching assistant in EU Law for Professors François Van der Mensbrugghe and Nicolas de Sadeleer at Université Saint-Louis in Brussels.


French, English, Dutch


Best Lawyers - Litigation 
Legal 500 - Litigation 


  • Columbia Law School, LL.M., 2016
  • Brussels School of Competition, LL.M., 2014
  • University of Ghent, Exchange programme, 2011
  • University of Louvain, Master of  Laws, 2011
  • Saint-Louis University (USL), Brussels, Bachelor of Law, 2009


Quentin is the author and editor of the International Litigation Blog (www.international-litigation-blog.com) which offers posts and discussions on developments and hot topics in the field of international litigation and arbitration.

“Fortis’s Settlement: A Comparative Case Study of Securities Class Action Mechanisms in Europe and the United States” (Business Law International, 2017).

“Achmea: Consequences on Applicable Law and ISDS Clauses in Extra-EU BITs and Future EU Trade and Investment Agreements” (European Papers, Vol. 4, 2019, No. 1).

“Ordonnance européenne de saisie conservatoire des comptes bancaires : la Cour de Justice de l’Union européenne préserve l’équilibre entre les intérêts des créanciers et les droits de la défense des débiteurs” (together with Margot Vogels, RDC/TBH, 2020).
“The role of treaty drafting in ensuring the binding nature and enforcement of international rulings handed down against States or international institutions: A comparison of EU and US case-law” (LawTTip, 2020).
“Investment Arbitration under Intra-EU BITs”, in José Rafael Mata Dona and Nikos Lavranos (ed), International Arbitration and EU Law (Edward Elgar Publishing Ltd) (together with Isabelle Van Damme).
“De rechtspraak van het Hof van Justitie over investeringsarbitrage onder intra-EU en extra-EU investeringsverdragen” (together with Isabelle Van Damme, SEW, 2020).


The impact of the Achmea judgment on EU trade and investment agreements with third countries (CEPS, Brussels, 26 June 2018).

The role of treaty drafting in ensuring the binding nature and enforcement of international rulings handed down against States or international institutions: A comparison of EU and US case-law (III LawTTIP, King’s College London Dickson Poon School of Law, 22 March 2019).

Investment Arbitration and EU Law (CEPANI 40, Brussels, 8 May 2019).

Possibility to enter into an inter se agreement in order to remove intra-EU investment arbitration proceedings from the scope of the ECT (5th EFILA, London, 30 January 2020).

Bar admission


Notable assignments

  • Advising and representing the Republic of Benin during the UNCITRAL's discussions on the reform of investor-State dispute settlement

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