Upon his return, he studied to become a set designer and later created backdrops for music halls including Casino de Paris and the Folies Bergère.

His first documentary, The Blood of Beasts (French: Le Sang des Bêtes) was a graphic film of a day inside a Paris slaughterhouse.

Franju's third film commissioned by the French government, Hôtel des Invalides (1951), was a look at life inside a veterans' hospital.

[1] With Head Against the Wall (French: La tête contre les murs) in 1958, Franju turned toward fiction feature films.

Franju had a long history of friendship with well-known surrealists including André Breton, and the influence of this movement is extremely evident in his works.

Throughout his documentary Le Sang des bêtes, for example, Franju reminds the audience just how strange everyday life can be.

Walter Benjamin argued that surrealism must "disturb capitalist culture's mythic assumptions of a rationalized evolving history" which is done by provoking a simultaneous interpretation of the past and the present.

For example, "La Mer" plays during a sequence in the slaughterhouse, comparing the lyrics to aspects of the slaughter, forcing the audience to interpret the love song in new and horrific ways.

During the most graphic grafting scene in the film a large importance is placed on surgical lamps, the scalpel being used, gloves, masks, and operating tables.

During one scene, loud, disrupting noises of an airplane and church bells are heard while Dr. Genessier and Louise bury a failed facial graft candidate.