I don't speak French, but I can understand a lot of it as my wife is from France and I spent some time there. This show is very dark and the further along you go the darker it gets. The story itself is about a French city where people keep getting what looks to be spontaneous combustion occurring to them. The story surrounds a man with clear mental trauma, in fact I would say most of the characters have been through mental trauma including the protagonists.
I will give this film a 6/10 as it holds some intrigue with a major mystery basically being a whodunnit style of film. It does hold some entertainment value so give it a whirl if you can handle mature, dark entertainment.