Your best bet is just to wait until you get there and go to an ATM machine.
Use your debit card to avoid the cash advance fees that come with a credit card's withdrawal from an ATM.
For the OP, how much cash do you think you'll need? France actually accepts credit and debit cards. It's not like you'll be traveling through Alabama.....
And the exchange rate is almost a non-issue if you're talking about exchanging a smallish amount of dollars for euros. A 1 cent change in the exchange rate (which would be a big change in a day, or even in a week sometimes) means only a one dollar difference when exchanging a hundred dollars. Even $500 dollars would only mean $5 difference. It's not significant enough to fret over.