Massacre of Pleasure (1966)

Jean-Pierre, a superintendent of detectives, narrates this story of police investigating three murders and discovering that their leads take them to the heart of a white slavery ring that is also in the drug trade. Men set up parties, invite young women, and then drug them, kidnap them, and sell them off to brothels. We meet Willie (a one-eyed thug), Pretty Boy (a sadist), a fat Greek who is the money launderer, and Jules, the big boss. Jules needs cash quick, so his greed also helps the police follow his trail. The police use informants, including women with drug habits, to get their first breaks. Then, the flics' net slowly closes.