Pokemon X/Y. At least two videos of have hit YouTube already and the cause seems to be loading a file where the player has saved in Lumiose City. The game locks up when loading the file, so if you're currently playing you may want to avoid saving within Lumiose City.
Lumiose City is the main metropolis of the Kalos region in Pokemon X/Y. In the center of the city stands the Prism Tower, which serves as its symbol and prime example the city's design was heavily inspired by Paris, France.
We've contacted Nintendo to confirm the company is aware of the situation and working on a fix. We'll be sure to update this post with Nintendo's response when we get it.