At the end of the car chase on the cliff road, the Ford's front panel falls down and the logo is gone. A few scenes later, the front looks almost intact with the logo perfectly standing on the hood.
Ousmane barely makes it under the forklift when driving a go-kart and then it is shown much higher on the very next shot.
After Francois applies lotion to the dancer's back, he wipes his hands on the front of his trousers creating large noticeable stains. In the next scene going down a set of stairs with Ousmane, the stains on his trousers are gone.
There is no positive discrimination policy in France.
It is physically impossible for a man to be severed in half by a high tension wire from that fall.
When he dies in the strip bar, the veins on the dead goon' s bald head are showing prominently, revealing that the actor is holding his breath. When dead, the heart stops pushing the blood in the veins (and arteries) and they simply collapse and are much less visible.
Obvious fake French-Swiss border post awkwardly signaled by a Swiss flag pinned on a tin roof.
At 1:11'52", Mercier says "I understand" three times. The first two times, his lips do not move on the reverse shot.
Julien picks up the tooth without without signaling it first to the coroner's team on scene and without any precautions; he could potentially have destroyed evidence.