Lumiose City's name may be derived from Paris's nickname, "La Ville-Lumière" which means "The City of Light".
There used to be a glitch where saving in the Lumiose City outskirts would instantly corrupt the save file and freeze the game. If it occurred, players would have to format the save and start over. it was particularly easy to encounter, as unsuspecting players would be tempted to save in what is easily the largest and most disorienting city in Kalos.
If a player went to the second floor of an unnamed building, a supposed "Ghost figure" of a Hex Maniac would come out of the elevator, walk by the player and mutter something. This Hex Maniac cannot be encountered again.