The Law Firm

In ancient Greece, the prôreus was a lookout who seconded the vessel’s captain. As one author explained it, “…the second technique to avoid submerged rocks was to have a lookout in the prow of the vessel; this prôreus or prorates; under the orders of the captain (kybernétès), was responsible for watching for dangers ahead of the vessel. He nevertheless was more than a simple lookout. He was truly a second officer to the captain due to his thorough knowledge of the vessel and its layout…” (free translation from "Navigation et Géographie dans l'Antiquité Greco-Romaine, La Terre Vue de la Mer", Jean-Marie Kowalski, Picard, 2012, page 39). 

Similarly, the Prôreus law firm acts in the interests of companies and the business they conduct. Through its own thorough knowledge of competition law, it helps them to avoid perils ahead or to turn obstacles into opportunities. 

To offer the most focused, responsive and efficient analysis possible, Prôreus focuses solely on competition law. These practical technical skills are enhanced by more “academic” work (articles, participation in research projects or work groups such as the Afnor Association for drafting compliance standards) and training provided to universities and companies. 

Nevertheless, these technical skills are tools only, and not an end to themselves. Prôreus is at watch to provide you with the most operational solutions possible, as a proactive business partner, whether in an advisory role or at your side in litigation. 

Finally, Prôreus is committed to a straightforward relationship with its clients. The firm seeks to be a partner, available and ready to listen to your thoughts and questions in what we hope to be a long-term relationship of trust.



 Emmanuel Dieny - Partner













  •  Law studies at the University of Caen Normandie (licence in law in 1991 – French equivalent of the BA), Lyon (master in business law in 1992), Toulouse (post-graduate degrees in business law and taxation in 1993) and Strasbourg (Professional Attorney’s Certification in 1996)
  • Admitted to the Paris Bar in 1997
  • He first practiced in a French niche law firm specialised in competition law (Vogel & Vogel, from 1997 to 2002); he was then associate in the competition law departments of two American firms, Coudert Frères (2002-2004) and Orrick (2004-2006).  These three firms gave him experience in complex, high-profile matters, for a clientele comprised principally of major French and international businesses
  • Opened his own law firm in March 2006 

Emmanuel Dieny is also a lecturer in competition law at the University of Caen Normandie 

  • Anticompetitive agreements, abuse of domination, Merger, Competition litigation, presentations at the DJCE (post-graduate business law degree programme) since 2008
  • Merger law, Intellectual Property and Competition Law, presentations to post-graduate professional degree programme “Company and Business Law” since 2013

Member of the French association for the study of competition (AFEC)

Work languages

  • French
  • English


  Sophie Lachaud - Associate






  • Studies in law at the University of Paris XI (bachelor of law degree in 2015, Master 1 in Private Judicial Law in 2016 and Master 2 in Procedural Law in 2017), then at the school of Hautes Etudes Appliquées du Droit (Master's degree in Business Law, Competition and Regulation in 2018) and at the Paris Bar School (Certificat d'aptitude à la profession d'avocat - CAPA - in 2019)
  • Admitted to the Paris bar in 2020


  • Internships in the competition and commercial law departments of French law firms (Joffe & Associés in 2018, BCTG avocats in 2019) as well as at the Paris Court of Appeal in the chamber dedicated to financial delinquency (2016-2017)

        Member of the French association for the study of competition (AFEC)

        Working languages

  •  French
  •  English