Yannick Le Pennetier, better known as Yann, began his career as an artist, but soon became one of France's most popular scenario-writers. After spending several years in Brittany, he moved to Brussels. After working in the advertising and architecture fields, his earliest comic stories appeared in the "Carte Blance" section of Spirou in 1974. He then went to work for Curiositiy magazine for a while, but returned in Spirou to begin a fruitful collaboration with Didier Conrad. They became infamous for their satirical illustrations on the tops of the pages, and most notably, their 'Les Innomables' series in 1980. While Yann drew and Conrad wrote the first story of this series, the duo switched duties from the second series. This adult series didn't fit in the juvenile atmosphere of the magazine, which led to the comic's disappearance in 1983.
Yann and Conrad then transferred to Glénat publishers, where they began 'Bob Marone' in Circus, a parody on the famous 'Bob Morane' character by Henri Vernes. Around this time, Yann began focusing more and more on the scriptwriting, leaving the artwork to others. After breaking up with Conrad, Yann began several new collaborations.