Continuity mistake: When Marlon Brando's character demands 20% of the con game proceeds, David Niven points at him with a cigar he holds in his left hand. But when the shot cuts to a different angle, Niven's hands are both instantly in his robe pockets, and the cigar has disappeared. (00:42:30)
Revealing mistake: When Brando poses with a group of young women for a picture, we can see two signs in the background, "Hotel Deutschs-haus" and "Bayerishe Verein" - both of them in grammatically bad German. Correctly the signs should spell: "Hotel Deutschhaus" and "Bayerischer Verein".