do I need extra postage to send a letter to France?

Please settle this argument:

Can I use a regular current US stamp, or do I need extra postage to get it there?

If you put a 37 cent US stamp and send a letter to France expect to get it returned to you.

Even a postcard to France from the U.S. will run you 70 cents. 80 cents for an envelope.

http://ircalc.usps.gov/