Patents are presumed valid (C. Cass. com., October 20, 1964): nevertheless, they may be annulled if evidence to the contrary is adduced by the person invoking the invalidity (" actori incumbit probatio").
Chapter 1. Cause of invalidity of a French patent
Section 1.1. Principle
The possible nullities of a French patent are listed in the article L613-25 CPI.
The list of nullities is exhaustive (C. Cass. com., June 2, 1992, No. 90-21629 contra C. Cass. com., December 8, 1992, No. 91-14234 which adds a rule of inefficiency of a claim (in the event that the claim is not based on the description or is contradicted by the description, a condition which is, today, a cause of nullity)).
Section 1.2. Causes of nullity
The causes of invalidity of a French patent are:
- the subject matter of the French patent is not patentable under the articles:
- L611-10 CPI (non-invention, novelty, inventive step, industrial application);
- L611-11 CPI (novelty);
- L611-13 CPI (case of inopposability of a disclosure);
- L611-14 CPI (inventive step);
- L611-15 CPI (industrial application);
- L611-16 CPI or L611-17 CPI or L611-18 CPI or L611-19 CPI (exclusion from patentability).
- the patent does not disclose the invention sufficiently clearly and completely for a person skilled in the art to perform it;
- the subject matter of the patent extends beyond the content of the application as filed or, where the patent has been granted on the basis of a divisional application, whether its object extends beyond content of the original application as filed;
- after limitation, the scope of the protection conferred by the patent has been increased.
Section 1.3. Partial invalidity
A patent may also be partially canceled (L613-27 CPI which mentions this possibility)
Section 1.4. Possibility of limiting
In order to strengthen the patent, the patentee may limit it in the action for invalidity (L613-25 CPI).
Section 1.5. Relative or absolute nullity?
The nullities listed in the article L613-25 CPI are absolute nullities: any interested person can request the nullity of the patent.
Chapter 2. Cause of nullity of a French part of a European patent
Section 2.1. Principle
Section 2.2. Causes of nullity
The causes of invalidity of a European patent are:
- the subject matter of the European patent is not patentable under the articles:
- the European patent does not disclose the invention in a sufficiently clear and complete manner for a person skilled in the art to perform it (within the meaning of A83 CBE);
- the subject matter of the European patent extends beyond the content of the application as filed (A123 (2) EPC) or, where the patent has been issued on the basis of a divisional application or a new application filed under section 61, whether the subject matter of the patent extends beyond the content of the earlier application as filed (A76 (1) EPC);
- the protection conferred by the European patent has been extended (A123 (3) EPC); or
- the proprietor of the European patent was not entitled to obtain it (A60 (1) EPC).
Section 2.3. Partial invalidity
Partial invalidity of a patent is possible (A138 (2) EPC and L613-27 CPI which mentions this possibility) and must be declared as an amendment to the claims. Thus, a partial nullity can not involve only modifying the description or the drawings.
Section 2.4. Possibility of limiting
In national proceedings, the patentee must have the opportunity to limit his patent by amending the claims (A138 (3) EPC and L613-25 CPI) in order to respond to the objections raised. This limitation then serves as a basis for the procedure. The limitation of course has a retroactive effect (A68 CBE).
Section 2.5. Relative or absolute nullity?
The grounds for nullity are, in principle, absolute.
Nevertheless, as regards the last ground of nullity (ie if the patent was obtained by an unauthorized person), the Court of Cassation nevertheless decided that this ground of nullity drawn from theA138 (1) (e) EPC was relative in France (C. Cass. com, February 14, 2012 # 11-14288).