Plot hole: Francesca gives Guardi the note via the pig that "your services are no longer required," yet it is stated later that Guardi can neither read nor write.

Deliberate "mistake": The tiny hot air balloon that Francesca released in the debate room would never be able to support Casanova's weight.

Factual error: In the scene where Casanova and Francesca are going to be hung, notice that there is no trapdoor under their feet. This obviously was for safety reasons, but they could have at least painted lines to make it look like there was a trapdoor. It's most noticeable when they are fleeing the scene from on top of the gallows.

Continuity: In the bedroom scene the bedding at the head of the bed slightly changes from one position to another and then back again.

Audio problem: When we first see Francesca and her family in their house, in any wide shots showing Francesca's brother, Giovanni, his mouth is not moving in sync with what he is saying.