French production house Marathon Media is developing its first stereoscopic 3D animated feature.DreamWorks alum Jim Cox (“Over the Hedge”) will pen the $15 million family feature based on an original idea. Marathon general manager David Michel and prexy Vincent Chalvon Demersay will present the project to potential co-production partners in the fall. The group’s first animated feature, the $20 million “Totally Spies: The Movie!,” based on the hit TV series, was released across Europe in 2009 and was recently picked up by Cartoon Network in the U.S. Marathon has also kicked off production on the first two seasons of “Rekkit the Rabbit,” a $15 million comedy. “Rabbit,” which targets kids aged 6-11, centers on a suburban boy whose life is turned upside down after adopting Rekkit, a giant rabbit with magical powers from the planet Chakabrak. Marathon will introduce “Rabbit” to buyers at the Annecy Animation Festival this week and will launch the two series — comprising 52 13-minute episodes — at the Mipcom TV mart in Cannes in October, Michel said. The series has been pre-bought by Gallic commercial net TF1 and Disney Channel Europe. Marathon is one of Europe’s leading toon providers to the U.S. market, with all its animated series — including “Gormiti,” “Martin Mystery” and “Monster Buster Club” — having been sold to U.S. nets such as Cartoon Network, Nickelodeon and Disney XD.