Tensions are high over police violence in the southern French city of Marseille. A young man who was allegedly brutally attacked by police officers in June is now telling his story. A police officer remains in detention while the investigation proceeds. Meanwhile police are protesting the detention, saying they are the victims. The World’s Gerry Hadden reports from France, on the national conversation sparked by this and other recent cases that raise questions about police use of force against people of Arab and African descent.