Continuity mistake: When Jerry gets in Milo's car so that she can get cash to pay him for his paintings, they get into a dark green car. In the next shot they get out of a light (slightly greenish) blue car. (00:23:00)
Factual error: There is a scene with Gene Kelly dancing at the top of the steps in Montmartre, opposite Sacre Coeur Basilica. In the background you see the lights of the Eiffel Tower. I have seen the view from the top of these steps, and the Eiffel Tower is not visible.