Other mistake: The protagonist uses his belt to temporarily fix the movie projector. He has to keep his pants on with his hands, but that's only until he has to grab an object and the pants do drop. Then he is still belt-less but the gag ran its course and his pants are not falling off anymore, once was enough.
A Monster in Paris (2011)
1 other mistake - chronological order
Directed by: Bibo Bergeron
Starring: Francois Cluzet, Gad Elmaleh, Vanessa Paradis, Mathieu Chedid
Factual error: The term mayor of Paris was abolished from 1871 till 1977. But we see Victor Maynott wants to join the mayor campaign in 1910.