This doesn't invalidate your point whatsoever, obviously, but what Le Pen exactly said is "Les chambres à gaz sont un point de détail de l'histoire de la Deuxième Guerre mondiale", which basically means that they do existed, but wasn't that big of a deal. Which in a way is actually even more insulting.
The funny part is we decided to pronounce "chat" in perfect english, but the remaining letters will stay french no matter what.