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Hello Patrick,

I can help for the French part (I'm french).  You can find some gluten-free
food in any Natural food stores (MAGASIN DIETETIQUE). The products are very
good and they do not taste gluten-free at all. By the way, Gluten free in
french is SANS GLUTEN.

If you go to any restaurants, just ask if they put any flour in the sauce.
I can't think of a particular problem, just be careful in restaurants and
bring some food with you . The natural food stores are really great where I
used to live. I do not think Paris or Switzerland  should be a problem.
If you have any question or translation to do, do not hesitate to contact me.

Bon voyage !
Caroline