For short-term travelers, you can get an IDP (International Driving Permit) from AAA. Costs something like $20. It is NOT a license. It's your license translated into a bunch of languages. The IDP along with your U.S. driver's license is sufficient (you don't have to carry a translation of your U.S. license).
AAA IDP International Driving Permit
"Your IDP is a valid form of identification in 150 countries worldwide and contains your name, photo and driver information. It translates your identification information into 10 languages — so it speaks the language even if you don't. Most countries highly recommend an International Driving Permit."
For permanent moves, you can exchange your U.S. license for a full 12-point French license on arrival (with the proper visa). 50 cc scooters can be ridden with just a regular license. 125/150 cc and up require a motorcycle license.
I never had any trouble driving in Germany in '71 on my U.S. license. Even though we were told we didn't need passports, I knew better, and took mine. Your military I.D. was sufficient AS LONG AS YOU HAD MATCHING ORDERS. With a passport, I could travel as a civilian. Which I did. I used my TS/C security clearance to get free train rides (I knew which trains and which compartments were reserved for couriers; I just showed my clearance; no questions ever asked!). I was in and out of Austria all the time. Couldn't do that on a military I.D.