Toulon fell to a surprise 41-0 defeat to Bordeaux but, led by Jonny Wilkinson’s 26-point haul, they tamed fifth-placed Montpellier in style.
The hosts scored five tries as they moved 11 points ahead of Toulouse, who lost to Perpignan on Friday night.
Montpellier were hindered by early yellow cards for Yoann Audrin and Mamuka Gorgodze, with Springbok Joe Van Niekerk, Nick Kennedy, Benjamin Lapeyre, Matt Giteau and Ivan Roux all scoring tries.
Clermont took Toulouse’s place in second with a 56-3 bonus point win at home to Mont-de-Marsan.
Biarritz landed a blow to fourth-placed Castres with a 15-9 win in the Basque country, while Paris side Racing Metro beat Bayonne 15-10.
The other Parisian outfit, Stade Francais, gave Bordeaux a reality check with a 30-14 win, while Grenoble beat Agen 27-13.