I don't think this has ever been discussed here, it is very impropable, but I don't think it is 100% ASB.
The rules:
The Aim would be to have France as a souvereign country without ocupation troups, that gives the Chef de l'État Français Pétain a tremandous funeral when he dies in 1951.
France shouldn't lose much more than it's colonies (including Algeria) Alcsace-Loraine and the areas that were ceesed to Italy in 1940.
And it shouldn't be a Nazi-wank scenario...
some thoughts...
POD would be after July 10th 1940 and likely before the beginnig of Operation Barbarossa, since the French communists joining la Resistance really got it going.
D-Day isn't likely going to happen.
The important point is to somehow get France neutral, make the Wehrmacht leave the country and have the British accept this...
But how?