Remy Cabella cancelled out a rare goal from Maxwell as Paris Saint-Germain were held to a 1-1 draw at faltering defending champions Montpellier.
Both sides finished the match with ten men as Mamadou Sakho was dismissed for the visitors, while Younes Belhanda received his marching orders for Montpellier in a tetchy affair that saw PSG return to the Ligue 1 summit.
Marseille had provisionally assumed control of top spot earlier in the day following a 2-2 draw at home to Nice, but a point for Carlo Ancelotti's side at Stade de la Mosson was enough for the Parisians to usurp their arch-rivals on goal difference, albeit having played one game extra.
With Zlatan Ibrahimovic serving the first of his two-match suspension, Guillaume Hoarau was handed a rare start by Ancelotti, but the French striker's participation came to an abrupt end as he was substituted after just 12 minutes, with PSG forced to reshuffle following Sakho's red card for a professional foul on Gaetan Charbonnier.
Despite their numerical disadvantage, the capital club went in front on 37 minutes as Maxwell lofted an exquisite chip from just inside the area over a stranded Geoffrey Jourdren.
But the hosts restored parity on the hour mark as Cabella dispossessed Blaise Matuidi inside his own half and advanced into the box before arrowing a low strike into the far corner past a helpless Salvatore Sirigu.
Belhanda was then shown a second yellow card for a deliberate handball just five minutes later, leaving both sides to see out the game with ten men.