Naive tailor Leon lives in a flat with his sister Marie, who he believes men are coming to see to have their palms read. Today he will discover that Marie is a sex worker, and her fiancé is actually her pimp. But on this same day, Marie saves Arlette from suicide and the shy Leon falls for her.

A very seventies comedy, Love is Gay, Love is Sad stars non-actor Claude Melki as the naive brother, Bernadette Lafont as the lady of pleasure sister, Jean-Claude Marielle as the crafty pimp, and French pop singer Chantal Goya! Misunderstandings a gogo make for brilliant, made-in-France humor.