Article L613-9 of the French Intellectual Property Code
All acts transmitting or modifying the rights attached to a patent application or patent must, in order to be enforceable against third parties, be entered in a register, known as the National Patent Register, kept by the National Institute of Industrial Property. However, before it is entered, an act is enforceable against third parties who acquired rights after the date of that act, but who were aware of it when…