If the Banque de France offices in French St. Martin match their posted online currency exchange rates, presently that rate is $1.1295 U.S. dollars per euro. And, that matches what today's exchange rate which is at .89 euros per USD. With that said I don't know if you'll get that if you visit one of their offices in Marigot or Grand Case. Maybe someone else out there knows if they restrict this service only to account holders or charge a fee for doing this. Personally, I have never exchange to euros directly on St. Martin. If needed, I convert USD to euros at my local bank in the states.