Jean-Clair Todibo has joined Nice from Barcelona for a reported $10.1 million transfer fee.
The fee could rise to $18 million if add-ons are triggered.
Barcelona are also looking to offload Junior Firpo, Philippe Coutinho, Neto, Samuel Umtiti and Martin Braithwaite, but have yet to receive offers.
La Liga president Javier Tebas stated that Barcelona must cut their wage bill before making any new signings.
Barcelona president Joan Laporta, who has already made four signings, is looking to add four more players to the squad.