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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
  • Representative before the UPC


  • 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, 2022, 2023 and 2024
  • Distinguished in 2020, 2021, 2022, 2023 and 2024 in the “Recommended individuals” category by JUVE Patent (Field of expertise: Chemistry, Pharma and biotechnology)

Related news

Classifications and distinctions - 18 Jun 2024

Who’s Who Legal France – Ranking 2024 

Who’s Who Legal has announced the results of its 2024 review of leading patent & trademark attorneys in France. Regimbeau is pleased to announce the recognition of Jean-Robert Callon de…

By Martine Bloch-Weill Marie Audren Jean-Robert Callon de Lamarck Stéphanie Massin Célaire Emmanuel Potdevin and Thomas Moisand
Releases - 19 Mar 2024

JUVE Patent – 2024 Rankings

Juve Patent, a reference platform specialized in the European patent market, has recently published its annual ranking of the best patent practitioners in Europe for 2024.   This year, Regimbeau has…

By Emmanuelle Levy and Stéphanie Massin Célaire
Releases - 08 Mar 2024

International Women’s Rights Day – March, 8  

To celebrate International Women’s Rights Day, we are proud to highlight Regimbeau’s team of female partners, who embody excellence and creativity in the field of intellectual property.   Committed to diversity,…

By Marie Audren Martine Bloch-Weill Anne Boutaric Barbara Casadewall, Ph.D Frédérique Faivre Petit Emmanuelle Levy Stéphanie Massin Célaire Isabelle Thill Frédérique Durieux and Anne Seibel
Classifications and distinctions - 16 Aug 2023

Who’s Who Legal 2023

Who’s Who Legal has announced the results of its 2023 review of leading patent & trademark attorneys. Regimbeau is pleased to announce the national and international nomination of Jean-Robert Callon…

By Jean-Robert Callon de Lamarck Martine Bloch-Weill Marie Audren Stéphanie Massin Célaire Thomas Moisand and Emmanuel Potdevin
Releases - 19 Jul 2023

Unitary Patent and the Unified Patent Court: Regimbeau announces the second edition of its book dedicated to the landmark European initiative

Paris, 19 July 2023 – Regimbeau, a French and European intellectual property firm, announces the release of the second edition of its book providing economic stakeholders with an insight into…

By Anne Boutaric Franck Delamer Anne-Laure Deleuze, Ph.D Yves de Saint-Pern Frédérique Durieux Stéphanie Massin Célaire Eric Roussel Anne Seibel Julie Toueg, Ph.D and Aurélia Vavasseur, Ph.D
Meetings - 18 Apr 2023

BIO International Convention – June 5-8, 2023 – Boston

Stéphanie Massin Célaire and Nicolas Bouquin will be attending the BIO International Convention, the world’s leading pharmaceutical and biotech industry event, which will be held in Boston from Monday, June…

By Stéphanie Massin Célaire and Nicolas Bouquin, Ph.D
Classifications and distinctions - 14 Mar 2023

JUVE Patent – 2023 Rankings

JUVE Patent, a reference platform specialising in the European patent market, has published its ranking of the best patent practitioners in Europe. REGIMBEAU is ranked among the best firms in…

By Stéphanie Massin Célaire and Emmanuelle Levy
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, Stéphanie Massin Celaire, Emmanuelle Levy and Olivier Prats, IP Attorneys at Regimbeau, became Partners. “As Regimbeau continues to evolve and reinforce its…

By Anne Boutaric Stéphanie Massin Célaire Emmanuelle Levy and Olivier Prats