If you don't put a license on it then by default in many countries (such as the US) no one can use it for any purpose whatsoever as they have not been granted a

If you don't put a license on it then by default in many countries (such as the US) no one can use it for any purpose whatsoever as they have not been granted a license to do so. It sounds like from your quote this is the case for France also: your proprietary rights would expire based on some legal schedule (and one that the US has likely influenced to be extremely long). A license isn't how you restrict something that is by default unrestricted: a license is how you selectively unrestrict something that is by default restricted... it is a contract between you and someone else to grant them rights they don't normally have.