Naked Teenager(1979)

Original title: Monique et Julie, deux collégiennes en partouze

In a French girls' boarding school, things are going haywire. The new professor is seduced by the lusty students and the teacher turns out to be a dominatrix who wants to show the girls the right way. The shameless goings-on do not remain without consequences, Monique and Julie should leave the sinful institute, but the two precocious girls decide to work in a Parisian brothel after school to pay the school fees...