An International Guide to
Patent Case Management for Judges

13.4.1 Patent interpretation for validity and infringement

The interpretation of a patent and its claims is subject to the independent assessment of the judges on the merits. The Court of Cassation has therefore handed down only a limited number of rulings on the interpretation of claims: appeals are only admitted in cases of misrepresentation of claims.²²⁷

Based on early case law of the Court of Cassation,²²⁸ which is always applied by the competent courts, the aim of interpretation is to “give [the terms of the claims] their full significance.”²²⁹ The principle therefore remains that the interpretation of claims is mandatory but may not entail additions to the claims.²³⁰

In this context, French case law applies the principle, now recognized in a decision of the EPO Enlarged Board of Appeal,²³¹ under which “the description and any drawings are always referred to when interpreting the claims, and not just in the case of lack of clarity or ambiguity.”

The courts apply an identical rule of interpretation for both French and European patents, as with the text of Article L. 613-2 of the IPC²³² having been amended to be identical to Article 69(1) of the EPC.²³³ The Protocol on the Interpretation of Article 69 of the EPC does not apply directly to French patents, but its principles have now been integrated into the case law of the courts.

As indicated in Article L. 613-2 of the IPC and Article 69(1) of the EPC, such interpretation is based on the description and drawings of the patents.

However, alleged infringers may, in support of the interpretation they present, refer before the courts to disclosures made by the patentee to the INPI, the EPO or even the authorities that examined the foreign counterparts of the patent at issue.

In such cases, there can be no estoppel: the Court of Cassation has ruled that estoppel (contradicting oneself to the detriment of another) implies, in particular, common ground between the parties²³⁴ and that there is a contradiction during the judicial proceedings, in the same case.²³⁵ Estoppel therefore cannot be applied to either the EPO grant procedure or to an opposition procedure involving the same parties,²³⁶ and still less to a grant procedure in another country.²³⁷

Such disclosures – like the examination and opposition procedures, or the pleadings in foreign court proceedings – are factual evidence that magistrates may take into consideration.

As a result, many decisions contain references to disclosures made by the patentee in grant procedures (at the EPO or elsewhere); magistrates often refer to them as support for the interpretation that they reached on the basis of the description and drawings.²³⁸

In substance, the courts first apply the rule of interpretation to give the terms of the claims their full significance when these terms are not clear in themselves. For example, when there is a functional limitation, the Court of Cassation agreed with the Court of Appeal, which had consulted the description to understand the meaning of the limitation and to deduce the essential features of the claim.²³⁹ The claim involved was for a mass suitable for casting: the Court of Appeal noted in the description, on the one hand, that the suitability for casting depended on the water content and, on the other hand, on the lower value of the range mentioned in the description. It thereby deduced that, because the alleged infringer presented a significantly lower water content, this product did not reproduce the patent claim.

The interpretation may also involve taking into consideration the technical problem solved by the patent, in accordance with the traditional definition of an invention as a technical solution to a technical problem. As a result, courts may, in their interpretation, take into consideration the technical problem solved (even if it is not explicitly mentioned in the claims). The Court of Cassation expressly ruled on this in a widely discussed case.²⁴⁰

A similar approach was taken in a more recent ruling.²⁴¹ The patent concerned a medicine for piglets. The claims invoked were for a formulation and its use, independent of any method of administration. The defendant in the infringement proceedings maintained that there could be no infringement, given that the product that they marketed, even if it was covered by the wording of the claims, was administered by injection, whereas only the oral form was proposed in the patent description. The patentee maintained the opposite: that the method of administration was not mentioned in the claim and that the scope of protection could not be limited to a particular embodiment that was disclosed only in the description. He further maintained that oral administration was claimed in a dependent claim (not invoked).

The court noted that the full description, as well as the examples proposed therein, made reference to oral administration. The court also highlighted that the technical problem indicated in the application could not be posed in the same terms for administration by injection. It then emphasized that the inventive step in the proposed solution was linked to oral administration by citing the reasoning of the Opposition Division of the EPO.

The court therefore rejected the provisional prohibition measures against the product administered by injection, despite the lack of detail about the method of administration of the product claimed in the terms of claim 1, as read in the light of the description and, in particular, the definition of the technical problem raised and the solution proposed.

This judgment is representative of the rule of interpretation followed by French courts. It is important to highlight that the court not only addressed the technical problem, but also emphasized that the inventive step was justified only in terms of the method of administration (although not claimed).

Interpreting does not mean adding to claims: an invention is a technical solution to a technical problem posed in the description. Claims therefore cannot be read independently of the description, which does not serve simply to dispel uncertainties or a lack of clarity.

As indicated previously (Section 13.3.2.1), when assessing infringement, French judges have an additional freedom of interpretation linked to the assessment of the “essential aspects of the invention.”