Sloppy Marseille lost at struggling Reims 3-1 and opened the door for Paris Saint-Germain to possibly clinch a record-extending 13th Ligue 1 title on Saturday.
A victory at Saint-Etienne would guarantee PSG the title only also if Monaco and Nice draw in Saturday's late game.
Second-placed Marseille dominated before falling behind in the 29th minute. Japan forward Keito Nakamura wrong-footed defender Leonardo Balerdi inside the penalty area and curled the ball in for his ninth league goal.
Careless play led to the second goal as Reims broke from midfield and Nakamura shrugged off Valentin Rongier before setting up Mamadou Diakhon for a left-foot finish.