
- Profil
Témoignages
Collectés indépendamment par l'équipe de recherche du Legal 500.
‘ Marie-Hélène Tonnellier is a well-known name in the technology sector. She has incredible breadth of expertise and is always super-responsive.’
‘Marie-Hélène Tonnelier has great expertise and experience.’
‘The Oyat firm, and in particular its founding partner, Marie-Hélène Tonnellier, offers a very operational approach in their consulting activity. The solutions proposed are innovative but pragmatic and adapted to the size of their client and their prospects.’
‘The team is very easy to approach.’
‘Strong and diversified expertise and very good knowledge of several sectors of activity and markets.’
‘Marie-Hélène Tonnelier has a very high level of expertise and experience in the field.’
‘Very good business expertise and very good communication.'
‘We frequently work with the Oyat team on IT, e-commerce, data protection matters and more recently on AI matters. I particularly value their technical legal skills which are delivered through the lens of being highly commercial and pragmatic.'
Clients clés
- SOPRA STERIA
- NOUVELLE AQUITAINE MOBILITES
- NEOCASE
- MAINCARE
- IMKI
- KEYSQUARE
- EDREAMS ODIGEO
- THE METRICS FACTORY
- OMNES
- SNCF CONNECT
Points forts
- Assisted Eurovision on various matters in IT, data and telecommunications in particular in the negotiation of an IT agreement with an IT company from Israel, providing new features and functionalities implemented in the Eurovision’s IT system in order to facilitate the broadcast of its programmes.
- Assisting IMKI, an IT company which creates AI specialised for fashion designers, helping them to conceive and create fashion collections.
- Assisting Sopra Steria in several IT projects.
Avocats
Les grands avocats du marché
Avocats associés reconnus parmi les leaders du marché par leurs pairs et leurs clients, régulièrement présents dans les grands dossiers dans lesquels ils sont au premier plan.

Meilleurs collaborateurs
Jeunes avocats collaborateurs ou counsels qui se distinguent régulièrement par leur présence dans des dossiers importants du marché, et qui sont identifiés par le marché comme de jeunes talents à suivre.
Charlotte Barraco-David
Responsable de la pratique
Marie-Helene Tonnellier
Autres avocats clés
Charlotte Barraco-David