I don't recall any nudity or sex but there is some heavy foreplay and some games of domination. Not exactly kid friendly but not terribly explicit, either. I imagine it would be rated R if released in America today, but primarily for violence (some police brutality and a murder).
shareThere is some violence, but only a little blood in this.
There is one f-word (at least in the new subtitles from the Criterion Collection blu-ray).
There is a lot of skin shown on the main female character, but not much actual explicit nudity. There are a few frames where she is naked in a bathtub and you can see her nipples, but even there she is still somewhat obscured. There are a couple of kissing and love-making scenes, but nothing explicit.
The themes are very intense and fascistic throughout, with lots of repressive rhetoric and violent shouting, which could be frightening or too stressful for some viewers to watch.
It's an R-rated movie, but in my personal opinion it is only slightly past the maximum for a PG-13, as it is nowhere near the upper levels of explicit violent/sexual content and language that you experience in many R-rated movies.