Tim Cook himself warned everyone when the new iMacs were announced that they would be highly constrained. I don't think many of us thought it would be that long (and it hasn't been in North America, of course, but it only JUST started getting better), but on top of the extraordinary constraint you ordered a custom one -- from a reseller.
If I were you I'd cancel that order and buy it directly from Apple France. I suspect you will have it MUCH quicker that way. Not tomorrow, but a lot sooner.
Oh, and FWIW I'm sorry you've had to wait so incredibly long. It's not normally the case with Macs, but this new one uses some very innovative production techniques that apparently took QUITE a while to get under control.