Entering interests from a bank in france

[tgonnot]

Do I need to declare them, and if yes, how?

[californiasteven]

You just enter in under Wages & Income, Interest Income.  All you need is the name of the bank and the amount in US$.  If you want to be very correct you report the amount according to the exchange rates when the interest was received.  That's probably a good thing to do if the amount is very large.