Bordeaux climbed up to second spot with a 2-1 win at Le Mans, while PSG lost at Lorient.
Fernando Cavenaghi gave Bordeaux the lead on 14 minutes and Brazilian midfielder Fernando added a second goal eight minutes later.
Martin Douillard reduced the arrears on 35 minutes, but Le Mans finished the game with ten men after Gregory Cerdan was sent off 16 minutes from time.
Lorient piled the misery on struggling Paris Saint Germain with a 1-0 win at home.
An unfortunate own goal from Gregory Bourillon on 19 minutes condemned Paul Le Guen's men to another disappointing defeat.
Monaco piled the misery on basement boys Metz with a 4-1 victory.
Highly-rated forward Jeremy Menez gave Monaco the lead on the half hour and Frederic Piquionne doubled the advantage 60 seconds later.
Wilmer Aguirre pulled a goal back for Metz on 54 minutes, but Menez restored the two-goal cushion just past the hour mark.
Serge Gakpe wrapped up the win with Monaco's fourth six minute from time.
Marseille climbed into the top half of the table with a 3-1 victory over Valenciennes at Stade Velodrome.
Djibril Cisse broke the deadlock on 25 minutes and Julien Rodriguez doubled the lead six minutes into the second half.
Cisse grabbed his second of the contest on 75 minutes before Johan Audel netted a consolation for Valenciennes nine minutes from time.
Auxerre picked up a precious point after a 1-1 draw with fellow strugglers Strasbourg.
Daniel Niculae gave Auxerre a dream start with the opener after just four minutes, but James Fanchone's 85th minute equaliser earned the visitors a draw.
Ten-man Lille earned a 1-1 draw against struggling Sochaux.
Lille got off to the worst possible start when Mathieu Debuchy saw red after just four minutes.
Sochaux made their numerical advantage count on 37 minutes when Mevlut Erding made the breakthrough.
Stephan Lichtsteiner ensured a share of the spoils when he converted from the penalty spot on 52 minutes.
Goals from Geoffrey Dernis (12) and Batefimbi Gomis (84) gave St Etienne a 2-0 win over Rennes.
Caen missed the chance to close the gap on the leading pack after a 1-1 draw at Toulouse.
Nicolas Dieuze gave Toulouse the lead on 35 minutes, but Anthony Deroin struck on 69 minutes to give Caen a point.
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