Hi there! World Adventures can get a little buggy...
There is no known way to fix this using the game alone, so my question to you is: how comfortable are you about mods? Do you have any? If so which do you have?
If you are unfamiliar with mods, Twallan has two that are usually good for helping in these situations - Overwatch and Errortrap. If your Sim can be saved, it would likely have to come from a mod. I'm assuming you've tried Resetting them and everything else you can think of. Let me know if you're interested in trying out the mods (or if you need help in figuring out how to install them correctly).
Another thing you can try is to right before you go home, try going into edit-town mode in France. Save your household to the Simbin and open a new file and try again there. That's the only other option I can think of as trying to preserve your Sim if nothing else works.
