Patent and Sufficiency of Disclosure in France

We present here a decision by the Paris Court of Appeal rendered in April 2024, which, unusually, resulted in the revocation of a European patent on the grounds of insufficient disclosure.

What the Law Says

Sufficiency of disclosure is one of the fundamental requirements for ensuring the validity of a patent, both in France and across Europe.

In France, Article L. 613-25 of the Intellectual Property Code (IPC) states:
“A patent shall be declared invalid by court decision: […] (b) if it does not disclose the invention in a manner sufficiently clear and complete for a person skilled in the art to carry it out […]”.

This same requirement is expressed in Article 138(1) of the European Patent Convention (EPC), which provides:
“Subject to Article 139, a European patent may be revoked with effect in a Contracting State only on the grounds that: […] (b) the European patent does not disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art.”

This requirement for detailed description is based on a principle of balance. On one hand, the inventor (or the assignee) is granted the exclusive right to exploit the invention, giving them a competitive edge. On the other hand, in return, the inventor must fully disclose the essential elements for implementing the invention in order to contribute to technological progress and allow others to draw inspiration from it once the patent expires.

The description is thus decisive, as it must meet legal requirements without revealing critical information that could weaken the inventor’s position in the market.

The above articles refer to a “person skilled in the art” (we note, for example, that the Implementing Regulations of the EPC were recently amended to reflect this terminology), a fictional character considered to be a specialist in the field. This person is also assumed to know the prior art relevant to their field of expertise.

Thus, when reading the patent application or the granted patent, the skilled person must be able to implement the invention, relying on their theoretical and practical professional knowledge, and without undue effort.

Presentation of the Decision

In this decision of the Paris Court of Appeal dated April 26, 2024 (Division 5, Chamber 2, No. 22/09439), a European patent was revoked in France for insufficiency of disclosure.

The patentee, IMPLANTICA MARKETING LIMITED, had sued a competitor (AFFLUENT MEDICAL) and its subsidiary (MYOPOWERS MEDICAL TECHNOLOGIES France) for infringement, based on European patent EP1284691 granted for a device for treating urinary incontinence. As is typical, the competitors defended themselves by challenging the validity of the patent.

From IMPLANTICA’s patent, we note the following:

• two definitions of servo means are given in the description: the first being a “classic” and known operation, and the second being a “non-classical” operation tailored to the invention: (“Advantageously, a servo means is used. With servo means less force is needed for operating the adjustment device. The term ‘servo means’ encompasses the normal definition of a servo mechanism, i.e. an automatic device that controls large amounts of power by means of very small amounts of power, but may alternatively or additionally encompass the definition of a mechanism that transfers a weak force acting on a moving element having a long stroke into a strong force acting on another moving element having a short stroke. The servo means comprises a motor, preferably an electric motor, which may be reversible.”)
• the “non-classical” operation is claimed, asserting that servo means includes a motor and a mechanism that transforms a low-intensity force acting on a moving element with a long stroke into a high-intensity force acting on another moving element with a short stroke. This embodiment is illustrated in Figure 6 and detailed in the description.

The presiding judge at the Court of Appeal considered that the description only explains how the servo means is connected to the device but does not indicate how it operates. Similarly, neither the drawings nor the claims specify the implementation method of the servo means according to the definition provided, which is not the “classical” (or common) definition of a servomechanism.

At first glance, this viewpoint might be surprising since the description appears to present an embodiment of the “non-classical” servo means in Figure 6, and because requiring a description of the method of implementation of the servo means might seem quite demanding.

However, upon closer examination of the servo means feature, it becomes clear that it was introduced during the examination process. In response, the examiner had raised a clarity objection (Art. 84 EPC), since the servo means feature was defined in terms of result and had no functional relationship with the other elements of claim 1, making it unclear which functions of the servo means were part of the device of claim 1. Moreover, the examiner noted that even with amendments to claim 1 to address the clarity objection, an issue of inventive step would remain, because servo means were “widely known in the field,” and a skilled person seeking to reduce the force required for an action would naturally use a servo mechanism to convert a weak force into a strong force.

In response, IMPLANTICA amended the claims by adding structural elements to the servo means and argued that the examiner’s reasoning was based on hindsight, and that none of the cited documents provided any suggestion to reverse the operation of the servo means. Furthermore, IMPLANTICA noted that an embodiment of the servo means is indeed described in Figure 6 and that the operation of the servo means is explained.

It is worth noting that in its patent, IMPLANTICA only provides the functional relationships of the servo means but further explains how to control the restriction mechanism in its response to the EPO.

In its decision, the Paris Court of Appeal stated (emphasis added): “The description merely indicates the advantage of the device and the goal to be achieved. Indeed, contrary to what the patentee claims, the description only explains how the servo means is connected to the device but does not explain how it functions. Similarly, neither the drawings nor the claims specify the method for implementing the servo means as per the provided definition, which is not the usual definition of a servomechanism.”

Thus, the Paris Court of Appeal confirmed the decision of the Paris District Court and declared the claim invalid for insufficiency of disclosure, unlike the EPO which had accepted the patentee’s arguments during examination.

We can deduce from this ruling that to satisfy the sufficiency of disclosure requirement in France, it is essential to specify how the claimed means function as well as their method of implementation, particularly if the definition given differs from the “usual” one in the field.

With respect to assessing sufficiency of disclosure in France, it is also useful to recall the ruling by the Commercial Chamber of the French Court of Cassation on January 23, 2019 (appeal no. R/2016/28322), where the Court held that the skilled person may rely on reference works to implement the invention, as their professional knowledge is not limited solely to that directly deriving from their specific field of activity.

Conclusion

This ruling by the Paris Court of Appeal once again highlights how crucial the drafting of the description can be for the validity of a patent—particularly in how embodiments are presented. As is often the case following examination, and as seen with the IMPLANTICA patent, what may have seemed optional or secondary during drafting can ultimately become the core of the invention.

by Ourvashi KISSOONDOYAL and Clémence VALLÉE-THIOLLIER, April 1, 2025