The Soleau Envelope is an intellectual property protection tool used in France to establish a certain date for a creation without requiring it to be disclosed. While the Soleau Envelope is primarily intended for non-public inventions that have not yet been the subject of a patent application, it can be used for any type of creation, such as an invention, a business method or even know-how.
Historically, the Soleau Envelope originated from a patent filed in 1910 by Mr. Eugène Soleau. In its original 1986 format, the Soleau Envelope consisted of a double envelope, each containing a copy of the materials related to the creation such as plans, sketches and technical explanations. These materials had to fit within seven A4 pages due to technical constraints. Once filled and sealed, the Soleau Envelope could be submitted to the French Patent and Trademark Office (INPI) which would stamp it with the submission date. One part was kept by the INPI and the other was returned to the applicant. The INPI retained its copy for 5 years, renewable once. As of April 1, 2024 it is no longer possible to file the Soleau Envelope in its original format and the electronic version called e-Soleau must be used instead.
The e-Soleau format is much more flexible and currently allows for the submission of up to 2 GB of data in a maximum of 100 files, with a duration of up to 20 years (compared to 10 years for the original Soleau Envelope).
Finally, the main advantage of the Soleau Envelope, now e-Soleau is that it serves as proof of the precedence of the creation and can be used in the event of a subsequent dispute over intellectual property rights. However, it is important to note that it does not confer intellectual property rights per se, except for possibly establishing prior possession. It is merely a means of proof and does not guarantee the validity of the creation or the existence of prior rights.