Nottingham Forest sign defender Moussa Niakhate from Mainz

Nottingham Forest manager Steve Cooper has added to his squad with the signing of Moussa Niakhate (John Walton/PA)

Nottingham Forest have signed French defender Moussa Niakhate from Mainz, the Premier League newcomers have announced.

The 26-year-old has signed a three-year deal, with the option of a 12-month extension, at the City Ground.