A Notable Clarification from the French Supreme Court: Impact of Inventor Designation on Patent Validity and Standing to Bring Infringement Proceedings
In a judgment of 24 June 2026, the Commercial Chamber of the French Supreme Court (Cour de cassation) confirmed that an incorrect inventor designation when filing a patent application cannot affect the validity of the resulting patent or the patent proprietor’s standing to bring infringement proceedings, in the absence of any claim to ownership of that patent by the inventor concerned.
Background to the dispute
The dispute concerns pharmaceutical manufacturing processes developed in 1988-1989 within SOA, which was absorbed by SEAC in 1989. In 2005, SEAC entered into a partial contribution of assets agreement with Minakem. Minakem subsequently continued to exploit this technology and, in 2013, filed a French patent application protecting the manufacturing processes at issue (the Earlier Patent).
In 2014, MMLS, a company founded in 2012 by a former director of Minafin, Minakem’s parent company, filed a patent application concerning a similar process (the Later Patent).
Upon learning of that patent, Minakem brought, in 2017, an action against MMLS claiming ownership of the Later Patent and an infringement action against MMLS and its subsidiary M2I Salin in respect of its own Earlier Patent.
MMLS and M2I Salin were held liable at first instance and on appeal, but appealed to the Cour de cassation. The appellants challenged the validity of the Earlier Patent, arguing that its filing was fraudulent because the named inventor had allegedly been incorrectly identified.
They further argued that Minakem had failed to establish that it held the necessary rights in the invention covered by the Earlier Patent, whether under the rules governing employee inventions or through a transfer of rights, and therefore lacked standing to bring the action on that basis. In support, they contended that the 2005 partial contribution of assets agreement did not establish the transfer of either the process at issue or the corresponding right to the patent, because the schedules listing the transferred intangible assets had not been produced.
Patent validity: inventor designation and entitlement to the patent have no bearing on validity
The Cour de cassation rejected the first argument. It recalled that the grounds for invalidating a French patent are exhaustively listed in Article L. 613-25 of the French Intellectual Property Code and that “the fact that the applicant knows, when filing the patent application, that it is not entitled to the industrial property right affects neither the patentability nor the validity of the patent protecting the invention”.
The Court thus confirmed that an incorrect inventor designation or a lack of entitlement to the patent (i.e. the right to file a patent application for an invention) has no bearing on the validity of the resulting patent.
Standing to sue: the presumption in favour of the applicant
Relying on Article L. 611-6 of the French Intellectual Property Code, the Cour de cassation recalled that, in proceedings before the French National Institute of Industrial Property (INPI), the patent applicant is deemed to be entitled to the patent and that a challenge to entitlement cannot be used to contest the applicant’s standing or interest in bringing infringement proceedings. The only legal avenue available to a person deprived of their invention is the entitlement action provided for by Article L. 611-8 of the French Intellectual Property Code.
This approach is also consistent with longstanding case law: as early as 1994, the Paris Court of Appeal held that a patent applicant was presumed to be the owner unless proven otherwise (1) ; in 1999, the Bordeaux Court of Appeal stated that the failure to designate, or the incorrect designation of, the inventor was not a ground for patent invalidity (2) .
The 2026 judgment takes this principle further. Even where an applicant knows, at the time of filing, that it is not entitled to the patent, it retains, once registered as proprietor, standing to bring infringement proceedings against any third party unless and until an entitlement action brought against it succeeds. In the present case, the Court observed that none of the actual or alleged inventors had asserted any rights in the invention.
Practical implications
The judgment reaffirms and strengthens the presumption of entitlement in favour of the first patent applicant, while establishing a strict separation between the available legal remedies. Challenges to ownership remain possible, but must be brought by way of an entitlement action initiated by the party claiming to have been deprived of the invention.
For businesses, the decision highlights the importance of documenting ownership of inventions, transfers of assets, confidentiality measures and access to technical know-how, particularly where former directors or employees are involved in later patent filings in the same technical field.
Cour de cassation, Commercial Chamber, 24 June 2026, no. 24‑14.680
(1) Paris Court of Appeal, 4th Chamber, 24 May 1994, Carosserie Nouvelle (represented by Brouard Daude SCP) v. Decodts, PIBD 1994, 575, III, 493
(2) Bordeaux Court of Appeal, 1st Chamber, 15 February 1999, Laloubère v. INPI and Thomson-CSF, PIBD 1999, no. 684, III, 403