Christian Clavier plays Thenardier, who in the book (fraudulently) identifies himself as "The Sergeant of Napoleon." Clavier has also played Napoleon himself. An earlier production, Les Miserables (1978) had Ian Holm as Thenardier. Holm has also played Napoleon.
John Malkovich and Gerard Depardieu had already previously played together as the main characters of the adaptation of a french novel: in 1998, they both played respectively as Athos and Porthos in the Man in the Iron Mask.