Stéphanie Lapeyre-Castellane

Stéphanie Lapeyre-Castellane has been a member of the Paris Bar since 2015 and joined OYAT as a partner in 2026. She heads the ‘Personal Data and Cybersecurity’ practice and co-heads the ‘AI’ practice.

She began her career at August Debouzy, subsequently moving to DLA Piper.

Stéphanie specializes in new technology law and provides both advisory and litigation support to her clients on their innovative projects. Her clientele, mainly major French and international companies (GAFAM, CAC 40, Next 40, major public organizations), operate in a wide range of sectors including luxury goods, retail, media, energy, transport, healthcare, finance and technology.

She has developed a highly recognized expertise in all issues relating to the protection of personal data and cybersecurity, working on various topics including the implementation of GDPR compliance procedures, contract negotiations, investment operations, internal investigations, launching cutting-edge technologies (e.g. AI, connected objects and facial recognition), data transfers, targeted advertising and fraud prevention. She also assists her clients in the event of cyberattacks and data breaches, as well as helping them to comply with the cyber regulatory framework (NIS 2, DORA, etc.). Besides, she has solid experience in pre-litigation and litigation processes before the French Data Protection Authority (the CNIL), as well as in ‘personal data’ litigation before civil and criminal courts.

Finally, Stéphanie regularly advises companies on the strategic and legal issues relating to their AI projects, particularly with regard to implementing the obligations set out in the AI Act (qualifying actors, governance, etc.) and managing the risks inherent in this technology.

Her Oyat is on the beach of Saint Jean de Luz.

Education

• Sciences Po – Diploma in International Affairs
• Panthéon-Sorbonne Paris I University – Master 1 in Business Law
• Panthéon-Sorbonne Paris I University (with Paris-Saclay University) – Master 2 in Digital Creation Law

Languages

French, English

Activities

• Lecturer at Paris-Saclay University, Master II Data Protection