Good dope is becoming rare in the North of Paris. Drugstores are being raided by junkies and gangs are nervous, fighting each others: the 'Viets', the 'Blackies', the 'Arabs', the neo-nazis 'Justiciers' and some mean gays. Vincent (Daniel Auteuil) is the good cop coming from Marseilles where he was a gangster. He's a soft method guy but also kicks assses hard and throw lethal dialog lines when needed. With the precious help of 'l'Arbalète'* (Marisa Berenson**), a tox' prostitute ex-member of Vincent's former gang, he will try to put order in that mess. There's also a violent and racist cop (Marcel Bozzuffi), Algeria veteran with hard methods, whose role could be more than to protect and to serve.