The so-called PACTE law (for business growth and transformation), which was promulgated in May 2019, significantly amended the rules of legal proceedings involving industrial property rights in force in France.

In particular, patent nullity actions (and also trademark and design nullity actions) are no longer subject to statute of limitations.

Prior to the PACTE law, France had no special law establishing the statute of limitations for such actions. Therefore, French case law referred to general law and Article 2224 of the French civil code: patent nullity actions were time-barred within a five-year period.

New Article L. 615-8-1 of the French intellectual property code now provides that "a patent nullity action is not subject to any statute of limitations." The same provisions apply to trademarks (Article L. 714-3-1) and designs (Article L. 521-3-2).

The patent nullity action not being subject to any limitation period is one of the French parliament’s solutions to strengthen the quality and credibility of industrial property rights granted in France.

Indeed, before the PACTE law, the official examination of a patent application performed by the French patent office had some weaknesses. This examination was more a registration formality than a thorough check of the validity of the patent application. Indeed, the French patent office could only refuse to grant a patent application on the grounds of the invention being obviously not patentable. None of the other patent validity conditions, namely novelty, inventiveness and industrial application, could be grounds for the French patent office to refuse to grant a patent. As a result, we noted that statistically, the patents granted by the French patent office were more subject to revocation by the courts (therefore less “strong”) than the patents granted by the European patent office, since the examination performed by the French patent office did not effectively and efficiently allow to refuse objectively invalid patent applications.

The PACTE law (i) strengthens the French patent office’s examination of patent applications by allowing the French examiner to reject a patent application on the grounds of lack of inventive step or lack of industrial application, (ii) introduces new opposition proceeding against French granted patents before the French patent office (within a nine-month period starting on the granting date) and (iii) makes patent nullity actions imprescriptible.

These three new measures should strengthen French patents and allow to eliminate invalid French patents for which preserving a monopoly to the benefit of their owners is contrary to common interest and to the principle of free competition.

However, before the new law may achieve this objective, the wording of new Article L. 615-8-1 of the French intellectual property code raises questions for which answers will be expected from the courts, in particular with regard to the transitional period for the application of the new law.

Indeed, the new law indicates that the new provisions shall apply to "patents in force on May 23, 2019." If one considers that new Article L. 615-8-1 of the French intellectual property code applies to all patents that were in force on May 23, 2019 without exception, it would include patents for which the former five-year statute of limitations would already have expired: it would include patents which on May 23, 2019 were in force for more than five years, i.e. patents that were granted before May 23, 2014. However, such interpretation would question a fundamental principle under French law, mentioned in Article 2 of the French civil code, providing that the law applies only for the future. Admitting the application of new Article L. 615-8-1 to patents in force on May 23, 2019 for which the former five-year statute of limitations had already expired would infringe the principle prohibiting retroactive legislation.

It would appear more appropriate to consider that the reference to patents in force on May 23, 2019 refers only to French patents in force on May 23, 2019 for which the former five-year statute of limitations had not yet expired on such date (i.e. patents granted after May 23, 2014). Regarding the other patents (which were granted before May 23, 2014), one ground for revocation would however remain: the counterclaim for revocation within the context of a patent infringement action, this counterclaim already being imprescriptible1.

As for patents granted since and after May 23, 2019, although it is not stated explicitly in the law, it appears obvious that the new provisions apply to them, even if they were not technically "in force" on May 23, 2019.