Well, where are they?? I'd love to see France better represented in the UFC, or WEC, or Strikeforce or wherever.
The problem is MMA's still illegal in France. You basically have to go abroad to fight MMA.
From what Ive heard about the gyms and training facilities, you cant train everything at the same time. You either have grappling gyms or striking gyms etc.. Same problem, legislation.
The sport isn't sanctionned and it makes training and fighting so much harder.
ps- one last aspect which prevents French fighters from doing well in the promotions you mentioned is the fact that wrestling is pretty underdeveloped in France. Though they have good strikers/boxers and judokas.