There weren't any special effects (wirework, computer graphics...) used in 90% of the parkour scenes.
The bomb code is: 9293709B13
Alexandre Aja was originally hired to direct the movie.
The movie features an unspecified extract from the UFC (Ultimate Fighting Championship) series by Zuffa, LLC.
Visa d'exploitation en France: #110308
Several members of the gang in B13 wear American National Football League (NFL) jerseys from the New York Giants, New Orleans Saints, and the New York Jets. The production did not secure permission from the NFL Players Association to display any player's name, thus per the recommendation of the studio's lawyers, the names on the back were digitally removed before the film was released theatrically.
Even though Bibi Naceri co-wrote the script, he still had to audition for the part of Taha along with other actors.
Tony D'Amario was originally considered for the part of Taha, but finally got an offer to play K2.
The whole movie took 10 months for production (idea, script, casting, filming, etc), January 2004 - October 2004.
In the scene where Leito (David Belle) is being chased near the beginning of the film, the way in which he does it in is in fact an activity called Parkour and was invented by Belle himself, influenced by his father Raymond Belle.
In the prison transfer van, Damien says he is Fantomas. Fantomas is a serial killer and thief from French pulp novels, film serials, and more.