Idées Noires. I'm sure you can tell which one.
Tarrin said in an interview in this week's issue of Spirou magazine that the story will focus on Fantasio growing up and changing into an adult, but also explain Zantafio's descend to the dark side.
(Bad news for all Tarrin fangirls out there: In the same interview, Tarrin mentioned that his girlfriend is currently pregnant. ;) )
In the folder I uploaded, you'll also find a HQ version of this week's Spirou magazine cover. Enjoy!