☛ François Truffaut at Work by Carole Le Berre, tr. from French by Bill Krohn, New York: Phaidon, [2004]2005, flaps photograph (both front and back) by André Dino, December 1958. © MK2/André Dino.

This is a behind-the-scene photo depicting the shooting of the very last (and very famous) sequence of François Truffaut’s film Les 400 coups (The 400 Blows). It was shot by still photographer André Dino at Villers-sur-Mer (in Normandy) between December 16 and December 22 1958 (I got the date from Truffaut: A Biography by Antoine de Baecque and Serge Toubiana, tr. by Catherine Temerson, University of California Press, [1996]2000, p. 132). The film premiere at the 12th Cannes Film Festival on May 4th where it won the Award for Best Director (see official site) and was released in France on June 3rd of the same year.
Below is another behind-the-scene photo shot by André Dino most likely during the same days of December 1958 (source of hi-res version). It shows François Truffaut (left) and Jean-Pierre Léaud (right) sitting in the same Citroen 2CV used for the final tracking shot on the beach. Léaud appears to be rolling a cigarette:

André Dino (IMDb) was a still photographer on many iconic French films of the same period. He worked on Claude Chabrol’s Le Beau Serge (1958), on Jacques Tati’s Mon Oncle (1958) and Play Time (1967). He also played a small role in some of them.
I was quite surprised to find a picture of him with Jacques Tati on the set of Mon Oncle (I couldn’t track back the original source: I believe it was first uploaded to the Internet on October 2006 by the blog If Charlie Parker Was A Gunslinger):

There isn’t much information about André Dino online. The first two photographs shown above belong to the Collection Cahiers du Cinéma but aren’t accessible online (see its Photothèque). Some more behind-the scene photographs shot by Dino during the production of The 400 Blows are also kept at the Cinémathèque Française (see Cine-Ressources.net).

Finally, I found the following image in Carole Le Berre’s book, on page 26. While he was still searching for the definitive title for his film, François Truffaut filled a small index card with various ideas.