Claims, Priorities and Procedure: Lessons from the April 9, 2025 Decision Upholding the Revocation of a French Patent

In a judgment dated April 9, 2025, the Paris Court of Appeal upheld the decision of the Director General of the French Patent and Trademark Office (INPI), which had entirely revoked a French patent related to a device for simultaneously filling water balloons. This decision addresses several key issues in patent law: added subject-matter, the validity of priority claims, novelty in light of prior art, and the admissibility of auxiliary claim requests filed for the first time on appeal. Below is an analysis of the key points for patent professionals.

I. Added Subject-Matter: A Frequent Pitfall in Opposition Proceedings

One of the primary grounds for revocation was the addition of subject-matter beyond the content of the application as filed, in violation of Article L. 613-23-1 3° of the French Intellectual Property Code (CPI).

Claim 1, as granted, introduced a new feature: hollow tubes extending “in the same direction.” This formulation was not present in the original application in isolation. The Court found that this feature was always disclosed in conjunction with another one: the flaring of the tubes during filling, intended to address the technical problem of space optimization.

Relying on established case law, including decision G 2/10 of the EPO Enlarged Board of Appeal, the Court recalled that extracting an individual feature from a specific combination of features is only allowed if there are no functional or structural links between them. In this case, the description and figures made it clear that the direction and flaring of the tubes are technically interconnected, both contributing to solving the space management issue.

This intermediate generalisation was thus deemed inadmissible. As a result, the dependent claims (2–13) that incorporated this problematic feature were also found to contain added subject-matter and were annulled.

II. Priority Validity: A Strict Requirement for Identity of Invention

The second ground for revocation was the invalidity of the claimed priority for process claim 14. The patent in question claimed three U.S. priority filings (P1, P2, P3). However, the Court found that documents P1 and P2 did not unambiguously and directly disclose essential features of claim 14.

To benefit from a priority right under Article L. 612-7 CPI, the claimed subject-matter must be directly and unambiguously derivable from the priority application. This principle is strictly applied in both EPO and French practice. Here, since certain key technical features of claim 14 were missing or insufficiently disclosed in P1 and P2, only P3 (dated September 22, 2014) was deemed to be a valid priority.

This finding was particularly significant since it rendered several prior public disclosures—specifically, YouTube videos—citable against the novelty of the invention, as discussed below.

III. Novelty and Online Disclosures: YouTube as Prior Art

Claim 14 was also invalidated for lack of novelty (Article L. 613-23-1 1° CPI) based on three videos (D7, D8, D9) published before the valid priority date (P3 – September 22, 2014), showing the “Bunch o Balloons” product in operation.

The Court reiterated the standard for lack of novelty: the invention must be fully and clearly disclosed in a single prior art document that describes the same arrangement and operation for achieving the same technical result. In this case, the videos, which were publicly accessible on YouTube, showed the invention being demonstrated by its inventor.

The characteristics of the patented process—aligned tubes, simultaneous filling, and automatic sealing—were all visibly implemented in the product shown. The Court also upheld the INPI’s reliance on the publication dates of the videos, which were sufficiently reliable and uncontested.

This aspect of the ruling reinforces that online audio-visual disclosures can constitute valid prior art, provided that their content and publication dates are credible and verifiable. This underscores the importance of early, thorough prior art searches—including on informal platforms like YouTube—when preparing a patent application.

IV. Auxiliary Requests on Appeal: Strict Procedural Constraints

Finally, the Court ruled that the seventeen auxiliary requests to amend the claims, filed for the first time on appeal, were inadmissible under procedural rules.

While Article L. 613-23-3 CPI allows patentees to amend claims during opposition proceedings before the INPI, appeals are governed by distinct procedural rules (Articles L. 411-19 and R. 411-38 CPI). Under these provisions, parties may raise new arguments on appeal, but cannot submit new claims with a different scope of protection unless the changes result from new facts or third-party intervention.

The Court followed existing French case law which holds that each independent claim defines a distinct scope of protection. Accordingly, amending the claims introduces new claims with different legal effects, and thus constitutes new “prétentions” that are inadmissible on appeal unless already submitted to the INPI.

However, the Court leaves open a nuanced question: would new auxiliary requests be admissible if the opponent introduced new grounds of opposition or new prior art at the appellate stage? The answer remains unsettled and may require future clarification.

Conclusion

The April 9, 2025 ruling provides valuable guidance on core issues in patent opposition proceedings, including:

The strict prohibition of intermediate generalisations not supported by the original application,
The narrow interpretation of priority rights requiring an identity of invention,
The use of online disclosures as valid prior art, and
The limited procedural scope for introducing new claim sets on appeal.

This case exemplifies the risks associated with modifications during prosecution and highlights the importance of coherence and foresight throughout the lifecycle of a patent—from drafting to grant, and through opposition and appeal.

Antonin Staub, 2 June, 2025