Ghoulam joins Napoli, currently third in the Serie A table, on a permanent deal which will expire in 2018, acccording to a club statement.

"Napoli wish to announce the signing of Faouzi Ghoulam on a permanent deal from Saint Etienne. He has signed a contract until 2018," said the statement.

Napoli did not release financial details of the transaction although reports on Thursday said the transfer fee is expected to be six million euros ($8.1m).