While I'm not an expert in French legislation, I highly doubt that
it prohibits allowing other people to use your work for any purpose
whatsoever. They might consider it a licence as opposed to public
domain, but that doesn't make a difference in practice.
Well, I can tell you : it prohibits allowing other people to use your
work for any purpose whatsoever... (which is not the case with the
gfdl license for example).
We had such a discussion a few weeks ago.