In the opening intro scene, Jean-Claude Van Damme's comment about not being able to film in one shot was his own ad-lib, partly in response to Mabrouk El Mechri actually wanting to shoot the scene in one shot.
Mabrouk El Mechri agreed to rewrite the script on the condition he could meet Jean-Claude Van Damme first before starting the draft, so he wouldn't waste six months on something that Van Damme would veto.
The concept for the film originated when the producer had an agreement with Jean-Claude Van Damme to play himself in a movie. In the original screenplay Van Damme was portrayed more as a clown. Mabrouk El Mechri was brought on to rewrite, and was subsequently asked to direct.
The trivia item below may give away important plot points.
Jean-Claude Van Damme made Mabrouk El Mechri swear not to tell anyone about the content of the six minute monologue he delivers straight to the camera. So El Mechri booked off 2 hours in the 5th week of shooting, and called it the X scene. He had a big black curtain set up, as Van Damme is a shy person, and El Mechri didn't want him to make eye contact with anyone before or during the scene. When Van Damme talks about not wanting to die in the post office, that was the cue for the crew to bring him back into the post office by lowering the crane. There was a red light next to the camera to indicate when the camera was running empty of film.