The Artist (2011)

Continuity mistake: Peppy Miller is speaking with George Valentin on a stairwell as other people are walking up and down the stairs. At one point, a long shot shows a man in a black suit going up the stairs and passing George. In the following close-up of Peppy, the man has disappeared. Instead, two other men in light-colored suits are going up the stairs.

Trivia: This was the first Academy Award Best Picture winner produced by a non-speaking English country.