Right, I think the first issue is with the editing, pace was roughly there but it just seemed to stutter in places and when most of the actors seem to have come straight out of stage school the pace really needs to be right on the button(compare and contrast with the UK TV drama, Spooks).
The story was weak and watered down, too many jumps without any suggestion, a poor script and direction also.
Thirdly the female lead, Vahina Giocante, really should have been shown the door after the first week, too much overacting for me, I've seen comedians act better. However I haven't seen any of her other stuff though so it could have been just a duff one for her.
Simon Abkarian has played measured bad guys before and did pretty well but I'm afraid that poor old Gérard Lanvin just didn't have enough script to go on, they spent too much time on the Martyr when they could have worked more on his character.
Sorry I really had high hopes for this and really wanted to like it, I even watched it twice to make sure I wasn't missing anything, but remember this is my opinion I'm sure others will love it. they tried to take the Spooks concept and do a French big budget movie, perhaps they should have got a script re-write and got Mathieu Kassovitz to direct.