Nintendo is hard at work on a patch designed to repair the Lumiose game-save bug in Pokémon X and Y, according to the official Japanese Nintendo website.
Translated, the page says that Nintendo will deliver a fix to the 3DS eShop “in a few days.” In the meanwhile, Nintendo did post a helpful diagram showing which areas are best to save in and which areas are unsafe (pictured below). According to the diagram (colored in with blue), the entire outer ring of Lumiose is unsafe to save in. As are the side streets to the right and left of the Route 5 entrance to Lumiose. All buildings, however, are safe, including Poké Centers.
The bug, first reported by players a few days ago, causes Pokémon X and Y save files to become corrupted. Attempts to restarting the game land players in a half-rendered world and leaves their 3DS unresponsive. The bug has been found in North American, Japanese, and European versions of Pokémon X and Y.