The teenager was expected to move to Camp Nou in July, but Barca have snapped him up at the end of the window after striking a deal with his club
Barcelona have confirmed that Toulouse youngster Jean-Clair Todibo will join the club immediately after bringing forward a transfer previously agreed for the end of the current season.
Todibo, 19, was out of contract at the Ligue 1 side in June 2019, and had already struck terms with Barca to move on a free transfer when his current deal expires.
But after negotiations between the two clubs, the Catalans have now revealed that he will be presented as a new signing in the current window.
The 19-year-old will sign for the next four and a half seasons, through the end of the 2022/23 season.
Todibo will be presented as a Barca player on Friday and will wear the No. 6 jersey vacated by Denis Suarez when the midfielder moved on loan to Arsenal.
Todibo is the second defensive signing of the current window for Barcelona, who also recruited Valencia's Jeison Murillo on a loan deal.
Born in Cayenne, French Guyana, the player came up through the ranks of the Toulouse youth system after moving to the team in 2016.
This season he established himself in the heart of the Toulouse defence, but strained relations at the club with his refusal to sign a new contract.
The teenager made 10 starts in Ligue 1 for his club prior to being frozen out of the first team in November, scoring one goal.