Continuity mistake: When Freddy and Janet arrive at Lawrence's mansion as his house guests, they arrive at night. Lawrence takes them upstairs and asks Janet to waltz with him in his ballroom. The scene takes place only a few minutes after their arrival. As they begin to dance, Freddy crawls to the door and starts moaning. Lawrence then shuts the ballroom door in his face and resumes dancing with Janet. As the shot cuts back to them dancing, a large window is plainly in view and daylight is streaming in brightly through the sheer curtains.
Continuity mistake: Near the start of the movie, Marion arrives on the train to deflect Freddy away from Beaumont Sur Mer. In this scene there are four shots of her seated in the compartment. In the first three, her legs are crossed right over left, and in the fourth, left over right.
Visible crew/equipment: Upon seeing the dancers, when Freddy is rushed away in his wheelchair by Janet, the reflection of the boom operator chasing after them can be seen in the mirror on the wall that they are running along.