Total posts : 45366
As you said, they don’t care about the AM band, so we can trust that they are not roaming around looking for small milliwatt signals, and because there are no interested licensed users of AM, there is nobody to complain about you. So therefore it seems extremely unlikely anyone will even notice your transmission.
Another side of the law is the concept of “permission by omission.” That is, if what you are doing is not expressly forbidden, it is therefore allowed.
Instead of part 15 rules, which you do not have, the most important part of the French broadcast rules for you would be those sections that prohibit all forms of AM broadcast, what I would call “negative law.”
It is time for a change in the regulations so that France comes pace with the modern electronic age.