Goofs

In his final appearance Milan (Bernard Blier) uses a revolver with a silencer. Unlike pistols, revolvers don't have silencers because these would simply not work.

The car park "exit" is actually an entrance. It wouldn't make sense to place a speed-limit-sign next to a no-entry-sign. The false no-entry-sign is suspended by a string and another string pulls the white bar vertical when the crash is heard.

When Francois is hit by the bagpipe, he leaves a bloody trace on the floor. But when several men are lying shot on the floor, they don't leave the slightest stain of blood.

Christine offers Francois to see the other instruments she keeps in the cellar. Not so wise, because that seems to be where Milan and the others are sitting in front of the monitor.