Mathias Cassel better known as Rockin' Squat is a French MC of Brazilian descent. He is the son of the actor Jean-Pierre Cassel and the brother of Vincent Cassel and Cécile Cassel (Hollysiz). In the mid-80s, he created the famous rap group Assassin, becoming the first artist of this scene to mention politics and social problems in his records. The subjects of his rap songs include modern slavery ("Esclave 2000"), ecology ("Sauvons la Planete"), political prisoners ("Ecrire contre l'oubli")