Toulouse resisted a Racing 92 fightback to make it 10 Top14 matches unbeaten and return to the top of the table with a 34-29 win on Sunday.
Clermont Auvergne had briefly reached the summit after beating Bordeaux Begles a day earlier. But, in a match where the teams split eight tries in Paris, Toulouse replaced their rivals once again.
Arthur Bonneval and Sofiane Guitoune tries for Toulouse were twice answered by Finn Russell and Juan Imhoff to keep Racing – who earlier on Sunday announced the legendary Dan Carter is to return to the club – in touch.
However, Lucas Tauzin's five-pointer and a second penalty from Zack Holmes preceded the latter going over for the visitors' fourth try just before the hour.
Racing made a brave fight of it as Joe Rokocoko and Antoine Gibert touched down, while a penalty at the death from Ben Volavola at least earned a losing bonus point for Racing.
In Sunday's other fixture, Tawera Kerr-Barlow's late try – his second of the match – earned La Rochelle a nervy 28-21 victory at struggling Grenoble to go third.
La Rochelle ran in four tries, but Gaetan Germain kicked seven penalties to ensure the high-fliers had to do things the hard way.