Alassane Plea's goal earned Nice a 1-0 win over AS Nancy on Sunday that moves them top of Ligue 1.
Mario Balotelli scored twice as Nice beat Monaco 4-0 to go top of Ligue 1, while there were also wins for Lyon and Bordeaux.
Lyon missed the chance to climb up to third in Ligue 1 after they were held to a goalless draw against Marseille.
Robert Beric scored an injury-time leveller to deny PSG a return to the top of Ligue 1 as they were held to a 1-1 draw at home to St Etienne.
Paris Saint-Germain suffered their first league defeat since March as Monaco struck an early blow in the Ligue 1 title race.
Man Utd will face Fenerbahce, Feyenoord and Zorya Luhansk in the Europa League, while Southampton are in a group with Inter Milan.