Originally Posted by 3Cforme

If you redeem Delta miles intra-Europe, you will pay fuel surcharges equivalent to those charged by the operating carrier - Flying Blue's surcharges for AF/KL travel for example.

If you redeem Europe-US-Europe, you will pay fuel surcharges.

If you can start your award travel routines in the U.S. and ticket U.S.-Europe-U.S. you will avoid fuel surcharges even on AF/KL/AZ flights.