Right of prior personal possession

The prior user right is the right of a person who, in good faith, was in possession of an invention before the filing or priority date of a third party’s patent, to continue exploiting it notwithstanding that patent. It is provided for in Article L. 613-7 of the French Intellectual Property Code, available on Légifrance. The prior user right tempers the first-to-file rule: it protects the person who made the invention without disclosing or patenting it.

The conditions of the prior user right

First, the prior user must have been in possession of the invention, meaning complete and effective knowledge of it, not a mere project or a general idea. Second, that possession must predate the filing or priority date of the patent and be located on French territory. Third, it must be in good faith. The possessor must not have obtained the invention through misappropriation or in breach of an obligation of confidentiality. Since the possessed invention was not disclosed, it does not destroy the novelty of the patent, which remains valid.

Effects and evidence

The prior user may exploit the invention personally, for the needs of its business, notwithstanding the patent. The right may only be transferred together with the business, or the part of the business, to which it is attached. It does not allow the grant of licences. The burden of proving possession lies with the party invoking it. Proof may be adduced by any means: laboratory notebooks, the enveloppe Soleau, time-stamped deposits, bailiff reports, dated internal documents. The regime is comparable in most European states, and the unitary patent refers on this point to national laws.

Key points

In practice, the prior user right is a defence raised in response to a patent infringement action. It presupposes a policy of traceability of internal research, in particular where the company chooses secrecy over filing. The firm advises on that organisation and argues this defence before the Paris Judicial Court, as presented on the page defending against an infringement claim.