Why don't you just go to a AF ticket counter and buy a ZED ticket with Delta?
Or buy a ZED ticket issued for another airline and give it to Delta.

I do not understand very well why do you have to decide weeks before flying where do you want to fly later... it happened to me once trying to get to Morocco, with Royal Air Maroc, and ended up flying other airline because of the process (sending a letter, receiving the confirmation, going to a Royal AirMaroc ticket office in the city, issue the ticket, and then refunding the unused coupons...) I love the system of going to your ticket counter and issuing the ZEDs that you wish. Very straing forward.