Revealing mistake: As the grating descends on Raoul, in two shots, large bubbles are flowing downwards. It's obvious, the film was reversed. (01:59:15)
Revealing mistake: In an early scene Cole and his future wife watch fireworks over Paris through a doorway overlooking a balcony. The explosions are reflected on the glass of the open door, which is at an angle to the POV. But the CGI fireworks and their reflection in the glass are squashed to fit into the foreshortened pane of glass. In reality the reflected image would be like any mirror, with the image inverted left-for-right.