The Porno King (1976)

This is a documentary on the 70's French porn industry. There are generally two kinds of porn documentaries--those that actually take an insightful look behind the scenes, and those that are just an excuse to show a lot of nudity and XXX porn footage. This is actually somewhere in between. It's generously seasoned with porn footage, but there are also a lot of (fully-clothed) interviews, and they even talk to the owners of porn theaters, some typical porn customers (including some pre-adolescent boys who are walking by the the theater--I wonder what their parents thought of that?), as well as a guy who makes promotional billboards for porn movies although he claims never to have seen one!