Chumballs

Chumballs (French: "Les Chumballs") is a 2009 French/Belgian animated series that aired on France 5.
Premise.
An environmentally unlivable environment on Earth following a catastrophic event has driven humans to live underground. They dispatched robots called Chumballs out to the surface to restore Earth. The Chumballs are supposed to beam a signal down to the humans once their work is complete and confirm that the surface can be resided again. But the humans haven't received the signal, forgot the Chumballs, and are forced by the council to remain inside the Earth. Three kids, Solana, Stel, and Tom, and their robot Tago, leave the underground and explore the surface of Earth on a goal to search and reactivate the Chumballs.
Production.
"Chumballs" was based on the comic book series "L'odyssée du temps" by Maxime Péroz, a graduate of the École supérieure des arts décoratifs in Strasbourg, and Michèle Graveline. There was also an interactive "Chumballs" website that existed as of 2001.