Burden of proof (charge de la preuve)

The burden of proof is the obligation on a party to establish the facts on which the success of its claim depends, failing which it loses. Article 1353 of the French Civil Code provides that a person claiming performance of an obligation must prove it and that a person claiming to be released must prove the fact that extinguished the obligation. Article 9 of the French Code of Civil Procedure adds that each party must prove, in accordance with the law, the facts necessary for the success of its claim.

Guiding principles

Legal facts (faits juridiques) may be proved by any means, whereas legal acts (actes juridiques) are subject to stricter rules. The court may not order an investigative measure to make up for a party’s failure to adduce evidence. The Court of Cassation now accepts that evidence obtained unfairly or unlawfully may be produced where its production is indispensable to the exercise of the right to evidence and the interference with the conflicting rights remains strictly proportionate to the aim pursued. Any doubt benefits the party that does not bear the burden.

Evidence in patent matters

The patent proprietor must establish that the acts took place and that the claimed features are reproduced. The French Intellectual Property Code allows infringement to be proved by any means and provides for the saisie-contrefaçon to make this possible. Where the patent covers a process for obtaining a product, the court may, in accordance with Article 34 of the TRIPS Agreement, require the defendant to prove that the process it uses is different, in particular where the product is new. A party relying on the invalidity of the patent or on prior personal possession must, for its part, prove it.

Other rights and the UPC

In a non-use cancellation action against a trade mark, the burden of proving genuine use lies on the trade mark proprietor, which reverses the ordinary logic. In copyright, originality must be established by the party claiming protection. Before the Unified Patent Court, Article 54 of the Agreement places the burden of proving facts on the party relying on them, and Article 55 restates the reversal provided for processes. Protection of trade secrets often determines how exhibits are produced.

Key points

The burden of proof decides the outcome where the evidence remains inconclusive. The facts each party must establish, and the means of doing so, should be identified from the outset, whether through a saisie-contrefaçon, an official report (constat) or an investigative measure. The defendant should avoid taking on a burden that does not lie on it, unless the law imposes it, as in matters of processes or trade mark use.

---

This glossary entry is general in scope and does not constitute legal advice.

Dhenne Avocats litigates patent disputes before the Paris Judicial Court, the Paris Court of Appeal and the Unified Patent Court. Where the question arises in a real case, the useful moment is almost always before proceedings are issued.

Patent litigation · Unified Patent Court · UPC case law · Tell us about your situation