Tahar Rahim delivers a strong performance in this bleak and brutal prison film. His character, Mailk, is an eighteen-year-old without the ability to read who finds himself incarcerated for six years after assaulting an officer. Upon entering, he has virtually no safeguards beyond what he's wearing. The institution operates under the control of Luciani, portrayed by Niels Arestrup – a man with Corsican roots and around twenty enforcers at his disposal, along with influence over the prison staff. Finding that the Arab inmates are causing him trouble, he chooses the new prisoner to be his tool for carrying out killings. Initially frightened and unwilling, it becomes apparent that Mailk doesn't have an alternative; compliance will guarantee his safety and survival. He embraces this path, gaining Luciani’s favor while learning to read with the help of a fellow inmate named Ryad. By the midpoint of his sentence, he has gained self-assurance, is entrusted with increasingly sensitive assignments, and even experiences occasional periods of leave outside the prison walls. As the population of prisoners shifts, both Mailk and Luciani must adjust – an undertaking that proves difficult. The film does feel extended at times and takes a while to build momentum; however, once the characters and their potential for treachery become clear, it develops into a tightly paced and absorbing narrative that doesn't shy away from depicting a harsh, survival-of-the-fittest world. Arestrup is also very effective as the powerful figure who gradually recognizes that change isn’t something he handles well, nor does he possess patience or any prospect of release. While the plot is somewhat foreseeable, it provides an intense experience, portraying conflicts between criminals and cultures with a grounded realism, and the time passes quickly.

Source on TMDB