Lino Ventura wears a Cartier Tank

Jean Douléan is a Paris geography teacher raising his eighteen-year-old daughter Isabelle on his own. When she tells him she wants to drop out of her medical studies and move in with a boyfriend, the argument ends in the slap of the title. Lino Ventura plays the father and Isabelle Adjani, in one of her first roles, the daughter; Annie Girardot plays Hélène, Isabelle's mother, who has been living in England since the marriage ended.

A French watch site identifies the watch on his wrist as a yellow gold Cartier Tank on an alligator strap. A watch with a dark leather strap does show in the film, though the dial never comes clear enough to read it as one. Louis Cartier designed the Tank in 1917, its rectangular case and Roman-numeral dial flanked by the two upright bars that have defined the shape ever since. It is a dress watch, formal and quiet, the opposite of a sports model.