Clermont Auvergne moved to the Top 14 summit with a 32-23 victory over Toulouse on Sunday, while Brive's winless run extended to five matches with a 26-22 loss at Grenoble.
Racing 92's heavy 60-7 defeat to Montpellier on Saturday opened the door for Clermont to overtake them in the table, and they did just that with a fifth straight triumph.
Morgan Parra proved the key for the hosts at the Stade Marcel-Michelin, kicking 14 first-half points which included a conversion after Alivereti Raka's try.
Toulouse were reduced to 14 men in the 45th minute when Tala Gray was shown a red card for punching Flip van der Merwe, whose yellow card five minutes later preceded Gillian Galan's second try of the day.
However, Raka matched Galan when he touched down on the hour-mark and there was no looking back for the hosts.
Grenoble consigned Brive to a fifth match without a win in the Top 14 at the Stade des Alpes.
Two penalties from Gaetan Germain helped Brive to a 6-3 lead, but Steven Setephano crossed the line for a converted try that put the hosts ahead.
After successful kicks for Germain and Jonathan Wisniewski, Gio Aplon intercepted Matthieu Ugalde's pass and sprinted 80 metres to the try line as Grenoble took an 11-point lead into the interval.
Ugalde made up for his error with a 51st-minute try, but two missed penalties from Germain and an unsuccessful drop goal from Nicolas Bezy proved costly, even though Grenoble were temporarily reduced to 13 men late on following yellow cards for Aplon and Walter Desmaison.