French patent law, more specifically Article L. 613-7 of the French IP code, provides a defense in case of infringement in France based on a French patent or a French part of a European patent: the prior personal possession.
According to said Article L. 613-7 : “Any person who, in good faith, at the date of filing or priority date of a patent, was in possession of the invention which is the subject-matter of the patent, shall have the right to work the invention on a personal basis despite the existence of the patent.
The right conferred by this Article may only be transferred together with the business, enterprise or part of the enterprise to which it is attached”.
The case law further clarified the conditions under which such prior personal possession can be opposed to a patent, and specified four cumulative conditions to be met to invoke such defense:
- possession must be prior to the date of filing of the patent application or its earliest priority date when a priority is claimed,
- the technology possessed must be identical to the patented invention,
- possession must be located on French territory, and
- the person claiming possession must be acting in good faith.
A recent decision of Paris Court highlighted the importance of the identity of the technology possessed and of the patented invention: the prior personal possession opposed must be strictly identical to the patented invention, otherwise it cannot be invoked.
Also of importance is the fact that such prior personal possession must be located on French territory. Prior personal possession evidenced outside France will therefore be unenforceable.
For inventions for which France is a significant market, it can therefore be wise to timestamp the invention in France, especially when it takes time to draft the patent application, for example by filing an eSoleau enveloppe, a timestamping service by the French patent office, which allows to timestamp documents, without any publication, simply by hashing the document with the online tool. There is no specific format to comply with, however, the knowledge of the invention should be extensively described, with all embodiments and alternatives, to make sure such prior personal possession is admissible before Paris Court.