I thought some department had be reverting to 90kph for some time although the signs haven't been changed back.
So you could get 80kph roads with the old 90kph signs still in situ and 90kph roads with the new 80kph signs. Go figure that one.
I also read somewhere that they only give 5% grace on limits and I guess that will depend on what mood they are in as well.
Just plan a relaxed riding holiday in France, don't be in a hurry to get anywhere and don't enjoy the roads.
Sod it I think I'll go the long way round and give France a miss.