Guillaume Léonard is Counsel and a member of the firm’s Public Law team, advising on both transactional and litigation matters.
He regularly assists clients on matters involving highly complex issues in regulated or closely supervised sectors (energy, audiovisual, defence, health, aviation and airports, agriculture, etc.) and in the public sector (governance issues in state-owned companies, lobbying issues, etc.). He also has considerable expertise in matters relating to environmental law (pollution at industrial sites, the circular economy, etc.) and contracts (negotiating public contracts, assisting economic operators with public procurement procedures).
Guillaume also regularly represents clients in contentious matters. He assists clients in any type of dispute involving challenging the validity of administrative acts, whether individual acts (targeting specific entities) or regulatory acts (applying to a category of entities or applied generally), and potentially the validity of the law. He has a particularly keen interest in litigation strategies involving EU law and the French Constitution. Furthermore, he regularly represents economic operators in disputes arising in relation to contracts, whether pre- or post-signing (urgent applications to the administrative judge for interim measures prior to signing, appeals challenging the validity of a contract, appeals seeking compensation, disputes relating to performance of a contract).
Guillaume also has deep knowledge of the legal framework governing foreign direct investment in France and related issues.
In addition, Guillaume lectures on public law at the School of Public Affairs at Sciences Po Paris and has given seminars in administrative law at the University of Paris I Panthéon-Sorbonne. He is the co-rapporteur for the work currently being carried out by the Environmental Law Committee of the legal think-tank, the Club des Juristes, on infrastructure and the green transition.
