"Matz" is the pseudonym for French writer Alexis Nolent. He has written scripts for video games, a novel, and as Matz, a number of comics including Triggerman by Walter Hill. His graphic novel, Du plombe dan la tete a.k.a. Headshot, was adapted into the 2012 film, Bullet To The Head. See http://www.dargaud.com/bd/Auteurs/Matz for a bio in French.