hello, sorry for my english i’am french…
I’m ben i have the xbox one and the xbox 360…
i want to buy FH2 on 360 and One because a lot of friends are on the two …
Is it possible to create two different game (one game on xbox 360) and (one game on xbox one) with the same gamertag?
Sorry if you don’t understand my questions…
Ben
Bonjour Ben! Sorry my french doesn’t extend very far from hello I’m afraid. 
If you have both an Xbox 360 and Xbox One, and a copy of the game for each system, you will be able to play with the same gamertag. Both games will be separate from one another from what I understand, so your save won’t carry across the two. Think of them as two separate games.
I myself have both an Xbox 360 and Xbox One, and my gamertag DevlinGFS is on both consoles, allowing me to play on both systems and accrue gamerscore. However some features I have on Xbox One, aren’t there when I am on Xbox 360, such as expanded friends list on Xbox One not being view able on 360. Hope this helps.
Yeah, games on separate platforms are counted as separate games. Cloud sync does not overwrite the saves from separate games. You’ll see this by seeing them as separate games in your games list.