Answering myself. I think I recognized the brunette girl who sits with the guy as Olivia Pascal (who has done some impressive nude scenes herself). And after some googling on that topic I am reasonably sure that the blonde stripper is Bea Fiedler, a German erotic and B movie actress. The two starred together in a few flicks in the late 70s and early 80s, but most of them don't match this setting. This scene, I think, is from "Summer Night Fever" (1978), a German teensploitation comedy by Sigi Rothemund, a director who made a bunch of successful sexploitation movies in the 70s, before turning to mainstream TV in the early 80s.
The song is "Follow Me" by Amanda Lear. Anyone know what movie this scene is from? I remember seeing it in the 80's, it was a pretty big hit back then. But what's the movie, and the actress?