Monaco dropped points for the first time in Ligue 1 this season as a 1-1 draw at Strasbourg on Saturday ended their three-match winning run.
Sadibou Sane's own goal gave Strasbourg the lead shortly after half-time, but Paris Brunner blasted in a superb equaliser from 20 metres to ensure Monaco reclaimed top spot from Rennes.
Germany youth international Brunner has now scored five times in six games for Monaco in all competitions this term.
Rennes beat Marseille 1-0 on Friday to briefly move into first place, but Monaco moved back to the summit on goal difference.
They could be joined on 10 points later on Saturday by Paris FC or Lyon, who meet in the French capital.
Paris Saint-Germain are still seeking their first win of the domestic season as they head to unbeaten Brest on Sunday.
Luis Enrique's side began their quest to win a third consecutive Champions League title by thrashing Slovan Bratislava 6-1 in midweek.
However, they have collected just two points from their opening three matches in Ligue 1.
