it sounds funny, but paypal has a shipping department that will give you everything you need. At the post office you will need to pick up the clear sticky thing to put on the package, then put the three forms inside. (it will be open because they will take them out as it progressives and the reciever should onyl get one.). I always put 4 copies in just in case someone wants to be a smart ***.
But then, The last thing I shipped to france was a Phoenix Gold MS1000 amplifier, heavy and large SOB, package it like you would drop it down stairs.