Limitation period in patent nullity suits: is this the end?
The Paris High Court and the Paris Court of Appeals state that the limitation period under ordinary law (i.e. 5 years) applies to an action for patent revocation.
It is an error of law. Two brief explanations hereafter (and maybe a way out).
First, it does not comply with article 2224 of the Code civil. Article 2224 provides a limitation period for both actions in personam and actions in rem. Yet the action for patent revocation is neither one nor the other. It is not based on a debt obligation (action in personam), nor on a thing (action in rem). It is based on the defense of free competition. In this regard, we should remind that a patent right, as an exclusivity to operate an invention during a certain period of time, constitutes an exception to free competition. Therefore, as an exception, this right is only justified for patentable inventions. Rather, it is not justified for non-patentable inventions. In other words: the purpose of an action for revocation is mainly to avoid unjustified patents that will negatively affect competition.
Then, the purpose of a limitation period does not apply to it. Such a deadline aims at strengthening legal certainty. Thus, a right holder must act within a strict deadline when his right is infringed. Similarly, a right may be created over time, when a defect originally affecting it disappears. For instance, a trademark can acquire distinctiveness through use. However, on the contrary, in patent law, time may only be harmful. An invention which is not novel or inventive at the date of filing will not become novel or inventive afterwards. Rather, one could discover prior art that was not discussed during the examination phase. Eventually, a limitation period in patent nullity suits will only introduce uncertainty. On the one hand, there are still doubts concerning the starting point of the deadline. According to the case law: date of filing, date of grant or date of formal notice. There is no strict trend concerning this question. Besides, in any event, the plaintiff must prove he was unaware of the existence of the patent: the burden of proof is upon the plaintiff. On the other hand, the defect that originally affects the patent right will not disappear over time. To the contrary, one could discover after grant that a patent is void due to prior art which was not discussed during the examination phase. Therefore, legal protection is not needed and thus not justified because it strengthens situations of facts that will never comply with the legal system. Worse: potentially, a patentee will still be able to use a patent against someone else even after it is found to be invalid.
A change in the law could be the solution. The French legislator has already specified that there is no limitation period in patent nullity suits, but he did it in a text that depends on the ratification of UPC (Ordonnance n° 2018-341)… Thus, the Paris High Court reminded us recently that the limitation period is still applicable till the ratification of UPC (Paris High Court, September 6, 2018). However, perhaps the French legislator will put an end to this catastrophic case law very soon with a specific provision in the « PACTE » Law (Law for SMEs) that will be discussed in the Senate from the end of January (see our post « Loi PACTE : quid de la prescription des actions en nullité des titres de propriété industrielle ? »).