Petra von Kant is a successful fashion designer -- arrogant, caustic, and self-satisfied. She mistreats Marlene (her secretary, maid, and co-designer). Enter Karin, a 23-year-old beauty who wants to be a model. Petra falls in love with Karin and invites her to move in.
Criterion has released the film and calls to our attention the "claustrophobic cinematography". Indeed, how can it be anything other than claustrophobic when we never leave the room? Much of the two hours takes place in a bed, with little beyond. This is quite a minimalism, and suggests the film is based on a stage play.
Fassbinder is known for his modern German interpretations of Douglas Sirk. This is one of his Sirk-inspired works. Maybe not his best, though that is all in the eye of the beholder. A second viewing may change my opinion on the matter.