The characters of Marion's parents are played by Delpy's real life parents, Albert Delpy and Marie Pillet.
Marie Pillet, Julie's mother, was actually one of the '343 salopes' back in 1971.
Because of his commitment to the film Deja Vu (2006), Julie Delpy was unsure if Adam Goldberg would be available to be in her film. She was forced to push back shooting to accommodate his schedule but he eventually arrived on set, twelve hours late.
The book that the American tourist show to Jack is "The Da Vinci Code" by Dan Brown.