Charles Berberian

Charles Berbérian (born May 28, 1959, Baghdad) a French cartoonist and scriptwriter of Armenian origin most famous for their series of Franco-Belgian comics albums featuring the character Monsieur Jean, in collaboration with Philippe Dupuy. Their collaboration is notable as they share every aspect of creating their stories, from plot through layouts, pencils and inks, to the extent that it is impossible to detect who is responsible for what. But in 2003, they decided to again work on their own, and have since published solo material like Hanté by Dupuy in 2005.

Source: Charles Berberian on French Wikipedia; Dupuy and Berberian on Wikipedia.