Joshua Bell, who was the solo violinist on the sound track, was also the stunt violinist. When non-musician actors needed to be shown playing the violin in close-up, Bell would hide behind the actor, and his left hand would be the hand seen by the camera on the neck of the violin. According to an interview with Bell on NPR, he was scolded several times by director François Girard for overacting.
Cesca's Tarot deck appears to have been specially designed for the film. The five cards drawn are all Major Arcana and resemble the Tarot of Marseilles in design, except that the devil holds one prisoner instead of two on the Devil card, and the Chinese flag is discernible behind the figure in the Justice card.
When Frederick Pope prepares to play his original, inspired piece in the rotunda, just after the conductor raises his staff you can see Joshua Bell (who is the actual solo violinist who performed on the movie soundtrack) as one of the violinists in the orchestra.
The Vienna section of the movie concerns itself with a boy named Kaspar who is described as an orphan and a wild child. This is probably a reference to Werner Herzog's film The Enigma of Kaspar Hauser (1974), which also concerns itself with a wild child named Kaspar, and which is also in German.