They had some really cool rigged cars and things that were different that they would tow behind the camera car that were actually on these trailers that manipulated side to side and stuff like they were getting hit, and actually put the actor right in the middle of the chase.
In France they spend six months training policemen, then they give them a gun and put them on the streets, and I don't know that that's enough. The film's not against the police - although I think that if someone wants to be a cop there's got to be a problem.