In Pool 4, Brive thumped Italian club L'Aquila 64-22, with backrower Alexandre Maleyrie scoring twice.
The French side ran in 10 tries at Parc Municipal de Brive, with former France winger Ludovic Valbon also bagging a brace.
Veteran Test prop Christian Califano scored a crucial try as Agen turned a 6-all halftime deadlock into a 23-6 win over Pau in Pool 2.
Fullback Arnaud Mathet added another try as Pau were confined to two penalty goals from Argentinian outside-half Gonzalo Quesada.
Bayonne scored four tries to beat Toulon 28-19 in Pool 3. The visitors scored three converted tries to open up a 21-0 lead at halftime, with outside-half Henri Vermis' second-half five-pointer holding off a Toulon comeback.