It is understood that Sunderland have agreed a fee with Le Havre for the full-back and have been given permission to hold talks with the player about a move to the Stadium of Light.
The 18-year-old has been linked with the likes of Arsenal and Cardiff, but now Sunderland are in pole position to land the left-back.
Mendy has also attracted the interest of French clubs such as Marseille and Lyon, but the player is keen to try his luck in England.
Paolo Di Canio has already brought seven new faces to the Stadium of Light and he is hoping to make Mendy his eighth new signing and the Frenchman will help fill the void left by Danny Rose's return to Tottenham.