Mr. Slimami is an Algerian retiree living in Paris who witnesses a murder while taking a walk one evening. He's spotted by the assailant, but Slimami manages to slip away before being caught. The victim turned out to be a prominent businessman, and police are soon searching for the witness as well as the killers. Slimami does not want to step forward, both as a matter of personal safety and because he prefers to let the French police handle their own affairs. His son Alilou, a budding journalist, openly decries the failure of the witness to come forward as a black mark on the Muslim community in Paris, unaware that the man in question is his father.