The original French title of the film comes from a line in Charles Trenet's song "Que reste-t-il de nos amours?" which is also used as the film's signature tune.
The New Wave was already ten years old, but this was the first time a film by one of its core members received the prestigious yearly critics award, the Prix Louis Delluc.
A series of five films directed by François Truffaut has been named "The Adventures of Antoine Doinel." They consist of the following, in order: Truffault's directorial debut Os Incompreendidos (1959), which introduces us to the 14-year-old Doinel, a neglected, troubled Parisian boy. Doinel's second appearance was in the short film Antoine e Colette (1962), which was part of the anthology film O Amor aos 20 Anos (1962). In it, Doinel, now 17 years old, becomes obsessed with Colette, a music student, but she only wants to be friends. This film, the third installment, shows a more mature Doinel, after a dishonorable military discharge, in two unstable romantic relationships with Christine and Fabienne. In the fourth foray, Domicilio Conjugal (1970), Doinel and Christine are married but he suddenly becomes obsessed with a young Japanese woman. Doinel's final fifth adventure comes to a close in O Amor em Fuga (1979), where his romantic attentions shift from his ex-wife Christine to record seller Sabine.
The book that Doinel reads in the lobby hotel scene is "La Sirène du MIssissipi", the film François Truffaut would direct after this one.
The book that Doinel reads in the first scene is Le Lys dans la vallée (The Lily in the Valley) by Honoré de Balzac.