Mathias Cassel (né Mathias Crochon) was born on 7 September 1970 in Paris, the son of actor Jean-Pierre Cassel and Sabine Cassel-Lanfranchi, former editor-in-chief of the gastronomic pages of American Elle. He comes from a family of artists: his brother is actor Vincent Cassel and his half-sister actress Cécile Cassel, also known as HollySiz as a singer. During his childhood, Mathias grew up in the United States, bathed in hip-hop culture, he began rap at the age of 11. Before his career as a rapper, he was a “tagger” known on the Parisian scene under the name of Squat and wrote texts at the same time.
In 1985, he founded Assassin with Solo. Assassin is one of the first groups to bring hip-hop to France, with “conscious” lyrics, delivering a political and social message. Like NTM or IAM, this group, considered to be a pioneer, has marked the history of French rap. It is also the first rap group to give a concert at the Olympia in 1993 and to have set up its own label, independent of the majors. From 1991 to 2004, the records of the group Assassin were self-produced and came out under the label Assassin Productions, the first independent label of French rap. From 2005, the albums were reissued under the new independent label, Livin' Astro, created in 2004 by Rockin' Squat, and under which, since, his solo albums have been released, each of them certified gold disc always meets a large audience, independently and without media support.
In April 2009, a new song leaked on the internet named Democratie Fasciste (Article 4) which featured Immortal Technique. The official release of the song and Rockin Squat's album "Confessions D'un Enfant Du Siècle Volume 2" was on May 12, 2009. The beat from the song was sampled from Wu-Tang Clan's song "Tearz". The song expresses the inequalities of the Third World and revolutionary events throughout history against tyranny and oppression. The song contains lyrics in English (Immortal Technique), French (Rockin' Squat) and brief shout outs in Spanish (Immortal Technique).[1] He made tracks with, among others, KRS-One, Seu Jorge, Tony Allen, Olodum, Ol Dirty Bastard, Cheick Tidiane Seck, El-P, RZA, R.A. the Rugged Man, Oxmo Puccino, Wise Intelligent, and Suprême NTM.[citation needed]