Before the doom and gloom squad arrive, I second what Andrew is saying. Go for it!
If you end up near us, my wife is Italian Swiss who studied in French and worked (me too) in South America. She has all three of your languages, all fluent, I have sufficient of all three to swim between totally OK and struggling through mostly.
Go for it! No idea what americans miss but there's an americans in france group so have a chat there. Being fluent helps no end (I have the same language mix as you (but have never got round to Spanish, one day...!) and OH and kids are french and all our (french) familly are here around us which really helps). Restaurant work is one of the few, very few sectors in France where you can still find work - a real plus for you both.
bonne chance / in bocca al lupo ;-)