Guillaume De Meersman advises clients in relation to antitrust related investigations and cases (notably horizontal and vertical agreements, abuse of dominant position, merger control, State aid, actions for damages, and compliance) as well as foreign investment and foreign subsidy control. 

Guillaume teaches competition law at the University of Paris-Panthéon-Assas, and previously lectured at HEC Paris Business School and the Paris Bar School (EFB).

Spoken Languages

  • Dutch
  • English
  • French


Guillaume’s practice covers a range of business sectors and he recently intervened: 

  • in international cartel investigation procedures before the European Commission, such as in the latter’s airfreight investigation and in the ensuing appeal against the European Commission’s decision before the EU General Court; 
  • in dawn raids (e.g., luxury and financial services sectors) and in subsequent procedures before the European Commission and national competition authorities; 
  • in an investigation before a foreign competition authority about an alleged abuse of dominant position in the energy sector, which implicated the successful triggering of the French blocking statute; 
  • in various merger control notifications to the European Commission and national competition authorities across the world (both Phase I and complex Phase II cases cleared subject to commitments), across a diverse range of sectors including financial services, retail, automotive, energy, and utilities; and
  • as global coordinator of an antitrust workstream that gathered 15 investors (banks and corporates) for the creation and notification to various competition authorities of the first blockchain-based platform that digitalises commodity trade finance, during his secondment to one of the investors (a bank).


King's College London, LLM, Competition Law

University of Paris Dauphine, Master ‘s degree in European and International Business Law


  • Paris