In the scene where Leito (David Belle) is being chased near the beginning of the film, he is using Parkour, which was invented by Belle himself and influenced by his father Raymond Belle. There weren't any special effects (wirework, computer graphics...) used in 90% of the Parkour scenes.
David Belle nailed the stunt where he jumps up and smashes through the tiny window above a door in just two takes.
The whole movie took 10 months for production (idea, script, casting, filming, etc), January 2004 - October 2004.
Despite common misunderstandings, the film is set in 2013 not 2010.
The opening script on screen say that the sectioning off of District 13 was actioned in 2010 and as the camera surveys the wall you see markings that say "completed Oct 2010" in French.
Then it says "Three years later" as the main film starts, making it 2013 and the sequel is 2016.
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.