Minor flaws, but on the whole a treat from the moment it starts to the end. Otherwise, the movie is pretty much solid. The music is consistent and fitting, so that's more of a matter of taste. It has been done before, but at least it's done well here. Two different guys team up and saves the day, overcome their differences and live happily ever after. What's there to dislike? Well, character development is the same-old. Dialouge seemed good too from what I got from the subtitles. Concrete and poverty works fine as scenery. The whole ghetto atmosphere works really well. For real, watch Heat) and not as repetitive and drawn-out as the usual ones.
The fighting scenes are cool too, and they at least partially real(for unreal, watch Hard Target or any other Van Damme movie. Smooth, fluid motion and crisp, no-bullshit camera-work makes it a real treat to the eye. In the wake of all the ruckus in France, this movie feels pretty realistic as a social commentary. What is there to like about this movie? Well, the plot is pretty good, even though I'd have much more trouble suspending my disbelief if it would not have been French.