Where do you find the Pokemon flutein X and y?

You can't find the Flutein in Pokemon X and Y. There is no Pokemon called Flutein.

Perhaps you're thinking of Fletchling, which is a Normal/Flying type Pokemon found in the Kalos region of X and Y. It evolves into Fletchinder and then Talonflame.

Are you sure you have the correct name? Please double check or provide more details about the Pokemon you're looking for.