Elie Baup's side beat the champions thanks to a late goal from Andre-Pierre Gignac, while elsewhere, Lorient rose to fourth, and Nancy's winless streak continued
Olympique Lyonnais failed to break clear of the chasing pack at the top of the Ligue 1 table, as they were held to a 0-0 draw by Evian.
The game itself was surprisingly turgid, as both sides cancelled each other out, with Alexandre Lacazette scuffing a shot wide after good work by Steed Malbranque.
Evian, who have been limited at the back due to the ongoing Africa Cup of Nations, did well to limit Lyon offensively, but up front, they themselves failed to test Remy Vercoutre in the Lyon goal.
Remi Garde's side stay top, depending on Paris Saint-Germain's result against Bordeaux in the weekend's final game on Sunday evening.
SOCHAUX 1-0 STADE DE REIMS
Sochaux moved out of the bottom three, to be replaced by Saturday's opponents Reims, after a 1-0 victory on a chilly afternoon in Montbeliard.
Kick-off was brought forward at Stade Auguste Bonal to avoid the freezing conditions, but it did not take long for Les Lionceaux to take the lead.
Yassin Mikari's powerful shot was turned around for a corner, in which Rafael Dias' delivery was met by Loic Poujol, as the hosts broke the deadlock.
Hubert Fournier's side struggled, and could have gone further behind after Dias' free-kick cannoned off the post, though Aissa Mande spurned a good opportunity for an equaliser.
The hosts followed up their shock 3-1 win over Marseille last weekend to earn another three points, while Reims have not won since October.
OLYMPIQUE DE MARSEILLE 3-2 MONTPELLIER
Marseille leapfrogged PSG to move second in the table after a thrilling, last-gasp 3-2 victory over champions Montpellier on Saturday.
On a breezy afternoon at Stade Velodrome, the visitors started brightly as they sought to shrug off the heartbreak of missing out on a place in the Coupe de la Ligue final earlier this week.
But it was Elie Baup's side who took the lead after 14 minutes when Joey Barton's cross was powerfully headed in by Andre Ayew. The lead lasted just three minutes when Emanuel Herrera beat the offside trap to round Steve Mandanda and silence the boisterous home crowd.
Rene Girard's side went ahead just after the break as John Utaka took advantage of some poor defending to put the visitors in the lead, before Marseille's late rally to avoid a second consecutive league defeat.
Ghana's loss at the Afcon became Marseille's gain as Jordan Ayew followed his brother on the scoresheet, tapping in after great work by Andre-Pierre Gignac, before the striker beat Daniel Congre to stroke the ball home in the 91st minute to steal all three points under the watchful eye of France and ex-Marseille coach Didier Deschamps.
AC AJACCIO 1-1 VALENCIENNES
Ajaccio were held to a frustrating 1-1 draw by 10-man Valenciennes, but could be aggrieved after a potential winner was chalked off.
Albert Emon's side were the better of the two in the first half, with Frederic Sammaritano and Adrian Mutu particularly active - the former firing wide after great work by the Romania international.
However, the former Juventus striker took the initiative to open the scoring, as he latched onto a loose ball in the box to fire past Nicolas Penneteau.
Benjamin Angoua was shown a red card for his tackle on the Ajaccio forward, before the hosts were awarded a penalty for another infringement in the area.
Mutu scored from the spot initially, but the referee ordered a re-take. The 34-year-old's second shot was then saved by Penneteau and Valenciennes' luck continued as Opa Nguette's equaliser ensured a share of the spoils.
FC LORIENT 3-2 ESTAC TROYES
Lorient climbed up to fourth provisionally after narrowly beating troubled Troyes 3-2 at Stade du Moustoir on Saturday evening.
Christian Gourcuff's side did not take long to build a commanding lead in a dominating first half for Les Merlus, as Kevin Monnet-Paquet and Enzo Reale struck within minutes of each other to put the hosts 2-0 up at the break.
Jeremie Brechet reduced the arrears midway through the second half, before Gregory Bourillon put the game out of sight with seven minutes to go.
Fabien Camus notched a consolation late on, but Troyes remain seven points adrift of safety, with those above them racking up points this weekend.
STADE BREST 0-1 SAINT-ETIENNE
Saint-Etienne followed up their magical week with a solid 1-0 win away to Stade Brest, as they moved back into the top 10 with victory on Saturday.
Christophe Galtier's side beat Lille on penalties earlier this week to book a place in April's Coupe de la Ligue final, and started the brighter of the two sides in Brittany.
Yohan Mollo's trickery enabled Brandao to score the game's winning goal five minutes after the break, though Mollo himself, as well as Eden Ben Basat, saw good chances go begging.
TOULOUSE 2-1 AS NANCY
Toulouse picked up their second win in three games with a comfortable 2-1 victory over bottom side Nancy, whose winless streak now stretches to 20 games.
Nancy, who saw coach Jean Fernandez quit the week before last, again looked particularly sluggish and stubborn as they looked for a first win since the opening day of the season.
Franck Tabanou, a reported target for Marseille this week, fired his side ahead 12 minutes into the second half, before bagging his second almost 20 minutes later as Le Tefece took command of the fixture at Stadium Municipal.
Lossemy Karaboue reduced the deficit, but Alain Casanova's side held out to record victory, as they move into ninth place.
BASTIA 0-2 STADE RENNES
Coupe de la Ligue finalists Rennes capped off their week by securing a comfortable 2-0 win over Bastia in Gueugnon on Sunday.
Yann M'Vila started on the bench after general manager Pierre Dreossi confirmed that the club had received offers from him, and would leave this week.
The hosts, who continue to play on the French mainland after their stadium ban, appeared distinctly second-best in the early exchanges, as Julian Feret shone.
Romain Alessandrini broke the deadlock half an hour in, calmly slotting home from Feret's deft pass, which evaded the reach of Mickael Landreau.
Mevlut Erding added a second on the hour, with a fine scissor-kick to settle the match, as Frederic Antoinetti's men continue their charge towards European football.
LOSC LILLE METROPOLE 0-2 OGC NICE
Nice's superb run in the top four continued as they completed a comfortable 2-0 away to Lille at Grand Stade Lille Metropole.
The visitors now only sit four points behind the richly-assembled Paris Saint-Germain, who play later on Sunday, as Claude Puel took the plaudits for engineering a win over his former side.
The game itself looked to be heading for a goalless draw before Renato Civelli's intervention 13 minutes from time nudged the Cote d'Azur club into a shock lead in northern France.
Sixteen-year-old Neal Maupay, already confirmed as the second youngest goalscorer in Ligue 1 history, picked up Les Aiglons' second to seal victory.