Some sexual dialogue throughout.
Valmot walks in on his servant and a maid having sex. The servant flees, taking his bedsheet with him, revealing the maid, fully nude (breasts and butt are shown). She offers herself to Valmont, but he refuses.
We see Valmont lying nude, face down on a bed as Cecile writes a letter on his back.
We see Valmont and Madame de Tourvel having sex, but there is no nudity as they are shown only from the neck-up with associated kissing/panting.