The highly-rated teenager will officially link up with the La Liga champions on July 1.
Barca have moved quickly to secure his services after seeing the youngster freed to enter into pre-contract talks as his current deal runs down.
A versatile operator who can fill in across the defensive line or in the middle of the park, Todibo is considered to be one of the most promising talents in European football.
He has already represented France at U20 level and big things are expected of him in the future.
Upon reaching an agreement to bring in a man they hope to see flourish in Catalunya, a statement released on Barca’s official website read: “Todibo is a tall, right-footed defender who can play at centre back and also in the centre of the midfield.
“At the youth level he often featured in the middle of the field given his ability on the ball.
“One of his best qualities is his physical presence and his ability in the air.
“At just 19 years of age, the young talent comes to FC Barcelona as one of the most promising players in European football in his position.”
Todibo was born in Cayenne, the capital of French Guyana, but linked up with Toulouse in 2016.
He progressed quickly through the ranks at the Ligue 1 club and was handed his competitive debut early in the 2018-19 campaign.
His bow came at the age of 18 in a meeting with Bordeaux.
He has gone on to make a further nine appearances this season, all of them as a starter.
Todibo has also recorded his first senior goal, with the target found as he netted a late equaliser in a 1-1 draw at Rennes in September.
He is now set to add much-needed depth to the defensive ranks at Camp Nou.
Barca have seen Samuel Umtiti struggle with knee problems this season, while Thomas Vermaelen’s fitness woes have continued and Gerard Pique will be 32 before the current campaign comes to a close.