Contact the store you bought the game from. If the key doesn't work when you try to redeem, it may be a stolen key.

First, tx for taking time to answer.

Well I don't think so, because the store where I bought this game has a very good reputation and the box was still under protection and seemed brand new :/

But I contacted them to ask whether they could bring me a solution or I give them the game back under condition of reimbursement.

So then I will buy a virtual version of the game, but I had a lot of stuff in the box like a map, a poster, etc. I'd like to keep if possible.

But I guess there is no really other solution than contact the store and taking another game... :/