A slow start at home to Toulouse ensured Sochaux would go into the final game of the Ligue 1 season still not safe from relegation.
The hosts need a draw at Bastia on the final day to be absolutely sure of staying in the top flight after their two-match winning run came to an end tonight.
Issiaga Sylla and Jean-Daniel Akpa-Akpro scored in the first 21 minutes of the first half to put Toulouse in control, and despite Giovanni Sio pulling one back before the break, the hosts could not find an equaliser, even after the visitors had Etienne Capoue sent off 15 minutes from time.
Defeat left them one place and three points above the bottom three.
Toulouse went ahead after 13 minutes when Adil Hermach's shot was punched clear by Simon Pouplin but only as far as Sylla, who volleyed the follow-up fiercely into the net.
Akpa-Akpro got the second eight minutes later, arriving in the area to convert Adrien Rabiot's low cross from the left.
Sochaux faced an uphill task to get back into the match, but they showed some fight with Rafael Dias testing Toulouse goalkeeper Ali Ahamada with a free-kick from long range and Cedric Kante having a shot deflected behind for a corner.
Sio gave the hosts hope in the 40th minute when he pounced on a weak pass from Hermach and dribbled past Capoue and Serge Aurier before surprising Ahamada with a low shot.
Sochaux tried to keep the pressure up after the break with Ryad Boudebouz trying his luck with a powerful drive from the edge of the area that Ahamada blocked.
At the other end, Franck Tabanou was denied by Pouplin.
The hosts got another lifeline when Capoue was shown a second yellow card for a hard tackle in the 75th minute, but they could not take advantage and Toulouse held on to ensure a nervous final day.