The filming of this and Nemico pubblico n. 1 - L'ora della fuga (2008), which lasted nine straight months, was done in reverse chronological order so that Vincent Cassel could progressively lose the weight he gained in preparation of the role, as Cassel knew he couldn't gain weight while filming.
Vincent Cassel gained 20 kgs (44 pounds) for the role during the four months leading up to the shoot.
Filmed back-to-back with Nemico pubblico n. 1 - L'ora della fuga (2008), which stands as the second half of the two-part story.
Producer Thomas Langmann first contacted Vincent Cassel about the Mesrine project in 2002, after the release of Jacques Audiard's Sulle mie labbra (2001) and Gaspar Noé's Irréversible (2002). Cassel initially accepted, but then bowed out as he found the script too "black and white". Benoît Magimel and Vincent Elbaz convinced by new helmer Jean-François Richet were then successively attached before Cassel returned, and especially Abdel Raouf Dafri's two-part script, claiming the screenwriter had succeeded in bringing the right tone to the picture and the character, bringing out all his darkness and paradoxes.
Jean-Pierre Cassel, Vincent's father, was originally set for the role of Jacques Mesrine's father (ultimately held by Michel Duchaussoy) in this and Nemico pubblico n. 1 - L'ora della fuga (2008).