Thanks for the reply. I know they do have prepaid envelopes - I'd like to know if anyone knows how to get one from here (without ordering one from the States). I can't seem to find an actual FedEx or DHL office here in France.Try UPS, Fedex or DHL, they should all do prepaid return envelope/waybills that you can put your address on before sending. Once you have a prepaid envelope from them, send it with your apostille request.
International postage coupons, (International Reply Coupons - IRC's) might just be looked as as too hard, don't know them, not our business to use them, or exchange them at a post office etc etc.