Audio problem: At the beginning of the school dance scene, there is a kid screaming "Sabbath. Sabbath." Later on, the same kid is shown to be the DJ, and when he is changing records, you can hear his voice still screaming "Sabbath. Sabbath." in the background, even though he is not saying it. (Revealed in DVD commentary).
Trivia: In the opening of the movie, David Duchovny is seen riding his bike through Paris. Apparently, in the shot where he is riding through the middle of traffic was not planned or rehearsed, he simply began riding a bicycle through heavy traffic while the camera man filmed him. He attributes this foolish choice to his "Having drank a glass of wine" earlier that night.