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After three years of academic research in France and six years’ experience as a patent engineer in an IP Law firm, Stéphanie Massin Célaire joined Regimbeau in 2008 and became Partner in 2014.

Stephanie has a vast experience in opposition proceedings, European oral proceedings and infringement litigation, especially in France, especially in the pharmaceutical and agribusiness fields.

In particular, Stéphanie defended the interests of her clients in disputes in several European countries while simultaneously representing them before the EPO in opposition proceedings involving numerous pharmaceutical companies.

Stéphanie also has expertise in freedom-to-operate analysis, global strategic support for start-ups and due diligence.

Stéphanie was a member of the CNCPI board then treasurer of the CNCPI for 6 years.


  • French Patent Attorney
  • European Patent Attorney


  • Master’s in Engineering (Institut National Agronomique Paris-Grignon)
  • MS in Biochemistry (Institut Gustave Roussy, Paris X- I.N.A P-G)
  • CEIPI Graduate (distinction in Patents)
  • Master of Business Law (Paris I)


  • IP Audit
  • Acquisition of IP Rights & Strategy
  • IP Prosecution & Portfolio Management
  • Pre-litigation & Litigation
  • Freedom to operate

Teaching / Representative positions

  • Lecturer at AgroParis Tech
  • Lecturer at Saclay University (Master 2 : Protection and Management of Innovation in Healthcare)


  • Nominated as one of the world’s leading patent practicioners by “Who’s Who Legal: Patents” in 2016, 2021 and 2022
  • Distinguished in 2020, 2021 and 2022 in the “Recommended individuals” category by JUVE Patent (Field of expertise: Chemistry, Pharma and biotechnology)

Related news

Webinars - 05 Apr 2022

Webinar – Implementation of the European Patent with Unitary Effect and the Unified Patent Court: the countdown is on!

The entry into force of the European patent with unitary effect and the Unified Patent Court is now expected for October 2022. What changes for European patent applicants in 2022?…

By Sylvain Thivillier Stéphanie Massin Célaire and Frédérique Durieux
Meetings - 23 Jan 2020

PACTE Act & New IP protection strategies

Regimbeau organizes a breakfast conference on the theme “PACTE Act & New IP protection strategies – Utility certificate, provisional patent & procedure of opposition to French patents”. Intervention of Stéphanie…

By Stéphanie Massin Célaire
Meetings - 26 Jun 2018

FORMATION : The basics of patent procedures

Regimbeau organizes a training on the theme “The basics of patent procedures”. Intervention of Stéphanie Massin Célaire;, Partner. For more information and registration:

By Stéphanie Massin Célaire
Releases - 09 Jan 2017

unitary patent and the unified patent court: regimbeau has released the 1st publication dedicated to this flagship european project

Paris, 9 January 2017 – REGIMBEAU, European and French IP Attorneys, announce the publication of a work dedicated to one of the major European projects: the Unitary Patent and the…

By Stéphanie Massin Célaire
Releases - 06 Mar 2014

Regimbeau continues to expand with the appointment of 4 new partners

Paris, 6 March 2014 – Anne BOGARD BOUTARIC, Stephanie CELAIRE, Emmanuelle LEVY and Olivier PRATS, IP Attorneys at REGIMBEAU, became Partners. “As REGIMBEAU continues to evolve and reinforce its position…

By Anne Bogard Boutaric Stéphanie Massin Célaire Emmanuelle Levy and Olivier Prats