When the lady from Paradise comes into the cafe to get out of the rain, her clothes are soaking wet though her hat and hair are bone dry.
Jan sees a train full of people being deported to a concentration camp. A closeup of one of the cars shows men within wearing gray and white striped uniforms. However, deportees were sent to the camps wearing their civilian clothes and weren't issued uniforms until after they arrived.
During the montage of Jan making love to Lise, stock footage is shown of SS men marching through the streets of Prague. The same footage is later reused by flipping the film from left to right, which is evident by the Nazi armbands moving from their left arms to their right arms and swastikas reversing direction.
In the cinema, where Dite is about to meet Liza, the first few rows of seats are from the original, 1930's era (made of wood, etc). From the fifth row on towards the back of the cinema the seats look like more modern day cinema seats.
In the Hotel Paris' restaurant scene a modern office building located across the street is clearly seen through the window.