This is the first animated adaptation (and first film & TV adaptation overall) of the famous Franco-Belgian comic-strip character Spirou, the adventurous young bellhop; his pet squirrel Spip (both created in 1938 by Rob-Vel); and his slightly older/taller sidekick, Fantasio (created for the strip in 1944 by Rob-Vel's successor, Jijé), a comical and skeptical reporter. The characters were made their most iconic by the third artist on the strip, André Franquin, who created almost all of the supporting characters, including the Count of Champignac, an eccentric scientist; Seccotine, a pretty young girl reporter, who is an invaluable ally for the heroes (and an occasional love interest for Spirou), despite the intense rivalry between her and Fantasio; the pompous Mayor of Champignac; Zantafio, Fantasio's evil cousin (a popular villain in the franchise); Zorglub, a misunderstood mad scientist (a popular anti-villain); and the lovable wild animal, Marsupilami (who got a spin-off comic-strip of his own).
This adaptation of "Spirou & Fantasio" is based on the acclaimed run by the writer/artist team of Tome and Janry (known collectively as "Tome & Janry"), who have the second-longest run on the strip behind André Franquin. Neither Zantafio nor Zorglub appear in this series, so the primary antagonists instead are Tome & Janry-created characters from the strip, including Don Vito "Lucky" Cortizone (a New York-based mafia gangster), his German assistant Von Schnabbel, and the renegade gynoid Cyanure (Cyanide, in English), who, in the comic, was a one-shot villainess, designed to resemble Marilyn Monroe; in the adaptation, she resembles a skinny woman with butch, spiky beige hair and dressed in black turtleneck sweater, pants, combat shoes, and green military vest (the very antithesis of the original character's more seductive appearance).