Looks like this challenge is much tougher than one would think! Props to you for going through with it. Your patience and endurance is admirable.

I can imagine you will find it hard to find a completely vegan dish at restaurants in France, especially if you are travelling through small towns and villages. But it is not mission impossible... if you need any tips on how to say certain things, let me know, and I will gladly help out (I'm originally from France)

Bon voyage et bon appétit 😉