Factual error: The gasolier, gas light fixture, in the entryway to Paula's aunt's mansion is the type/form that would have been used in a room, not in a hallway. The gasolier in the mansion bedroom used by Gregory Anton, Charles Boyer, is the type/form that would have been used in a hall and would not have been used in a bedroom.
Gaslight (1944)
1 factual error
Directed by: George Cukor
Starring: Joseph Cotten, Ingrid Bergman, Charles Boyer, Dame May Whitty, May Whitty
Continuity mistake: Gregory crumples the letter where Sergio Bauer is mentioned, but when Paula finds it later on it is perfectly folded and the wrinkles are gone.
Gregory Anton: You see how it is, Elizabeth.
Elizabeth: I see just how it is, sir.
Trivia: Gaslight was teenage Angela Lansbury's first film and first Academy Award nomination and Ingrid Bergman's first Academy Award win.