Mewtwo exist in this game, but what about Mew, anyone have him yet?
Mew is an Event Pokemon and will not be encountered outside of events and glitches/cheats/hacks. So, the answer to your question is no. Of course, you can Transfer any mew from past games and future events are possible. --- Steel Type alone is responsible for the slow Death of the Pokemon Franchise. Gym Leader Wulfric is mai Husbando!
Use the Flute on one of the Skiddo in Lumiose City. It'll get scared and run. Go to the Baa de Mer ranch and you'll find it there. It will run again. Then, go to Geosenge and use Strength on the remains of the HQ entrance. They'll fall open. The Skiddo will charge on in, headfirst, flying down the chute. Go rescue it, and on your way out, you'll encounter a Level 0 Mew. You have to use a Rare Candy on it to level it up to Level 1, then you can fight with it. --- Build a man a fire, keep him warm for a day. Set a man on fire, keep him warm for the rest of his life.