The Soleau envelope is a simple and convenient way to prove the creation date of an industrial property right to the INPI (French National Institute of Industrial Property). It contains a copy of the text, design, or model, divided into two perforated sections, each dated by the INPI upon receipt. One section is returned to the applicant, who can thus establish prior claim in the event of a dispute and benefit from a personal right of use, without becoming the owner of the trademark or registered concept.