OP, do you have a credit card with 0% fx fees? I know many cards in the US have it, Chase Sapphire, Amex Platinum, etc. If you have them, use them!
Otherwise, if you must have cash, just withdraw from a local bank in Euros.
Be careful though, the French really don't like Amex unless you go to top restaurants and hotels, in Nice you should have more luck, when I drove through France the other time all the petrol stations were Visa and MasterCard only!