Animville is a city located in France. It is the main setting of the series.
Animville was everything to the many humans that lived there. The city was originally suited to be in Africa as shown in Milk Diet, but it is hinted that the city itself is actually in Europe, because the appearance of the € (Euro) sign in the episode Olivia's Pimple serves as further proof for that.
In From Mumbai with Love, when the shot with the map, plane and path to Mumbai is shown, the start of the path is actually a dot that is located in Paris, France, which would mean that Animville might be located in France.
In Bicycle Crazy!, while Jack is holding a map of France, the camera zooms into Paris, showing another proof of Animville being located in France.