A "cultural tip": Métro stations in Paris are frequented by pickpockets, especially during high-traffic periods and where new arrivals are coming out of the train station from the airport. Easy-pickings for them with a steady flow of new targets. Men are advised to keep your wallet, cell phone, or other valuables in a secure place, not in your pocket!
Carte Bleue is a French group of "banking cards" (affiliated with VISA), like VISA itself, MasterCard, American Express, etc. Other French speaking countries don't use that particular card, Carte Bleue is a France-only network. I would also add that a Carte Bleue is not necessarily a credit card, it can be (and usually is) a debit card.
If you want to keep the precise meaning of a credit card, carte de crédit is the only translation that works everywhere. Carte bancaire (banking card) can be used too, and/but doesn't specify if you're speaking of a credit or debit card.