Jean-Pierre Melville regarded this as one of the greatest French films ever made.
Becker died two weeks after completing the film.
Director Jacques Becker used mainly non-actors for purposes of authenticity. In fact, one of his choices was actually involved in the 1947 escape.
La Sante prison was replicated right down to the smallest details, thanks to the help of the three actual members of the escape whom Becker hired to serve as production consultants.
Shot over a period of 10 weeks.