Jean-Clair Todibo joins fellow French defenders Samuel Umtiti and Clement Lenglet at Barcelona.
"The player's contract with Toulouse ends on 30 June this year and so he will join on a free transfer."
It added: "he comes to Barcelona as one of the most promising players in European football in his position."
Todibo joins fellow French defenders Samuel Umtiti and Clement Lenglet at Barcelona.
Central defence, however, has proven a problem area for the club this season, with Umtiti and Thomas Vermaelen both out injured.
According to Barcelona's statement, Todibo is "a tall, right-footed defender, who can play at centre back and also in the centre of the midfield."