In all of the games in which I checked, France was pretty much the only producer of Luxury Furniture. I would have built a few factories for it myself, but I'm always Laissez-Faire or Interventionist. In any case, I'm thinking that in your game, your own production of Luxury Furniture drove down the prices enough that France wasn't getting the same bang for its buck. I think the biggest lesson from all of this is that the algorithm for determining industrial score needs to be seriously, seriously reformed.