Nice missed the chance to go third in Ligue 1 when Toulouse came back from a goal down to beat them 2-1 at home on Sunday.
Terem Moffi gave Nice the early advantage when he fired past Guillaume Restes in the eighth minute.
Toulouse, however, who beat Monaco and Lille in their last two Ligue 1 outings, began to create the better chances in the second half and two goals in quick succession turned the game on its head.
In the 65th minute, Romain Perraud failed to cut out a pass to right wing Warren Kamanzi. His cross was met by Thijs Dallinga who headed his ninth goal of the season, his fourth in the last five matches.
Four minutes later, the 23-year-old Dutch striker turned supplier as he teed the ball up for Yann Gboho who swivelled round Pablo Rosario before crashing the ball past Nice goalkeeper Marcin Bulka, who could only get his fingertips on it, and into the roof of the net.
The win moved Toulouse up a place to tenth, leap-frogging Lyon who host Lens later on Sunday.
Nice remain in fifth, missing out on the chance to go above Monaco and Lille.
It was the first time that Nice had lost a game after leading since May 2022 against Lille, a run of 30 matches.
Paris Saint-Germain top the table in spite of their 0-0 draw with Monaco on Friday.
Second-placed Brest can close the gap to eight points, however, if they beat Le Havre on Sunday.
