Brest stumbled to a 1-1 home draw against managerless Reims in Ligue 1 on Friday, giving Lille the chance to leapfrog them this weekend in the race for Champions League qualification.
Marshall Munetsi headed Reims ahead in Brittany midway through the first half before Brest equalised on the stroke of halftime through Lilian Brassier.
Third-placed Brest, who had never finished higher than eighth before in the top flight, pressed for a winner but had to settle for a point, leaving them with only one win from their last five matches.
They are three points ahead of Lille, who visit Nantes on Sunday and have a marginally better goal difference.
Reims are winless in six outings and parted ways with coach Will Still at the start of month after the club slipped out of contention for European football.
Nice also remain in the mix for a Champions League spot following a 1-0 victory over Le Havre.
Jeremie Boga's 12th-minute goal extended Nice's unbeaten run to five games and took them to within a point of fourth-placed Lille.
The top three teams in Ligue 1 will qualify automatically for next season's revamped Champions League, while the side finishing fourth enters in the third qualifying round.
Auxerre clinched an immediate return to the first division after a 0-0 draw at Amiens wrapped up the Ligue 2 title.