Nintendo just acknowledged the problem with Pokémon X and Y, where saving inside Lumiose City can crash the game, and make you lose your progression. Looks like they're also planning to release a special application very soon, that will allow impacted users to restore their save data, though they don't give any date whatsoever.
They have a map where they show the areas where you should NOT save when in Lumiose City (in blue -- saving inside building is apparently safe) :
Google translate :
Source
Catch me with a PokéBall if old.
They have a map where they show the areas where you should NOT save when in Lumiose City (in blue -- saving inside building is apparently safe) :
Google translate :
We are preparing an application to recover saved game data for players whom this has happened to. This will be made available to download from Nintendo eShop as soon as possible..
Source
Catch me with a PokéBall if old.