Raoul is a big-headed delivery man/self proclaimed inventor, and is particularly attached to his modified delivery truck, Catherine, and his straw (though he usually denies this) coat. He is usually seen throughout the film with his best friend Emile. His love interest is 'The Angel of Montmartre', Lucille.
Raoul appears for the first time when Emile leaves the cinema and accompanies him to a store to buy a camera. He turns out to be allergic to bird feathers and not very good with his own gear. He even manages to prevent a thief from leaving with Emile's new camera without knowing it.
In the evening, the two go to the botanical garden to see the Professor, but the latter has gone to New York. Despite Charles, the monkey who guards the laboratory, Raoul cannot help but poke around and play with the Professor's products. He is filmed by Emile when he makes a sunflower grow gigantic and when two flasks collide to make a flea grow in the same way. Raoul, however, did not notice the monster he created himself and left the laboratory.
Days later, he delivers bottles of wine to the "The Rare Bird" cabaret and scares Lucille. The two argue and Lucille taunts him by saying that he can attend one of his shows only if he has the Legion of Honor on his jacket.
Immediately after, he discovers Francoeur on the images filmed by Emile and they are questioned and arrested by Inspector Paté. However, commissioner Victor Maynott decides to reward them because they increase his chances of being elected if he kills the chip. Raoul then asks for a Legion of Honor and goes to the cabaret with Emile.
They listen to Lucille and Francoeur sing and discover that it is the flea that they have unwittingly grown. The next day, Raoul and Emile attend a conference by Maynott who wants to kill Francoeur and go to warn Lucille. The latter hides them and the chip and Maynott leaves without finding anything.
The group puts a plan in place so that the commissioner thinks he is killing Francoeur but quickly realizes that he has been deceived. While he chases Francoeur, the others follow him to the Eiffel Tower and Raoul sacrifices his hay jacket and Catherine to succeed, to his great sadness.
He later thinks too that Francoeur is dead and convinces Lucille to sing at the cabaret. The singer makes him learn that the flea is alive and sings in her ear. With Charles and Emile, Raoul goes to the laboratory for taking same vials and make Francoeur grow up again. He then dances on stage with Lucille and the flea.
Raoul later goes to Lucille's dressing room and remembers a flashback where they were both little and Lucille had stolen his toy car. The two finally confess their love for each other and kiss.