In the first chase in Paris, a grey car is passed from the left and a white one is next. The next shot shows the taxi passing a grey car (which came out of nowhere) from the right, and then we're back to the original situation with the grey and white cars, this time passing the white one from the right, as expected.
Sandrine's body changes position on the car roof between the jump/crash shot from above and the street-level shot a few seconds later.
Near the end of the movie, every time a wide shot of the bad guy's boat is shown, several bad guys have the exact same positions and weird poses, even though the shots are not supposed to be happening at the same minute.
During the car chase with the sports car along the coastline, at some point a line of slowed-down cars (unvoluntary extras) can be spotted a few dozen yards behind the sports car.
When the taxi passes between two tramways, a reaction shot of Eddy in the taxi is shown. The driver is clearly the stuntman and not Franck Gastambide.
Tapping the phone button on the taxi interface calls the number you're thinking of, depending of the situation: first it's Régis, later on it's Eddy's sister. Both times, no number was inputted, not was a selection from a contact list made.
When the bad guys hijack a guy's car, the cameraman and the camera can be seen in the reflection of the left-side back window, right when the driver is punched.
When the taxi is first seen inside the container, it fills the entire space; there is almost no room to open the doors, not to mention getting near the doors or even entering the vehicle. But somehow, the next scene takes place inside the taxi still in the container.