The role of Blaze was written with
Bourvil in mind, which would have marked
Gérard Oury's fourth collaboration with the actor, and his third time pairing him alongside
Louis de Funès, after
The Sucker (1965) and
Don't Look Now... We're Being Shot At! (1966). After Bourvil passed away from cancer in September 1970, Oury and co-writer
Danièle Thompson were at a party talking to actress
Simone Signoret, who suggested her husband
Yves Montand take on the role, which was completely rewritten. Oury compared the two takes on the character to valets made famous in plays by
Molière, with Bourvil's being a "Sganarelle" and Montand's a "Scapin".