Factual error: Frank and Elise approaching to Venice by train. Train announcement says "Arrival at train station Santa Lucia in ten minutes". Landscape from the train window is green and hilly. I'm from Venice and no way you find such landscape 10 minutes from Venice Santa Lucia. Most probably you would see a gray Mestre, Venice inland city, or a completely flat and not green land (for at least 30 minutes from/to the train station of Venice). (00:19:30)
Factual error: When Frank and Elise arrive in Venice, they sail from the train station to a hotel which is also located on the Grand Canal (from the balcony we see the Rialto Bridge). However just after leaving the station, we see Saint Marc's Square from their boat from the other side of the lagoon. That is very far from the station - and not on the way to that hotel.
Factual error: As Frank walks on the roof, he is being filmed from different camera positions. Filming him from behind, the Rialto bridge is visible in the distance. Filming him running towards the camera, the Guggenheim terrace is in the distance. Not possible, because there is a bend of the Canal Grande between the bridge and the Guggenheim.
Factual error: When the two arrive in Venice, they check into the Hotel Danielli, an actual Venezia landmark which sits on the Lagoon, at least half a kilometer down from the Piazza San Marco When Johnny Depp goes to look out the window of their room, he is looking at the Rialto Bridge... a good 20-25 minute walk on a good day.
Factual error: In the boat chase on the Canal, Frank turns the wheel on his boat, and the boat turns sharply. But the boat is being dragged and the engine is not running. Turning the wheel will then make very little (or no) difference in its direction. Motorboats turn by the propeller turning, not with a rudder like a sailing boat.