Toulon gave debuts to their two All-Black recruits on Saturday but still lost for the second time in the French Top 14 this season, beaten 20-10 at Pau.
Reigning champions Castres battled back to beat Lyon 19-16 and ambitious Stade Francais also made it two wins in two by seeing off Bordeaux-Begles 20-8.
Liam Messam started in the back row for 2014 champions Toulon and had some storming moments but he also failed to deal with a high kick before the home team's first try.
Winger Julian Savea came on after an hour, by which time Toulon trailed, and could not change the result.
Toulon, who lost heavily at home to Racing 92 on the opening weekend, started strongly, inspired by Anthony Belleau, one of the French internationals who had also missed last week's game.
The fly half kicked through and Fijian Josua Tuisova gathered to score under the posts. Belleau converted.
After 20 minutes Toulon coach Patrice Collazo told a pitchside TV reporter: "We've already completed more passes than in the whole match last week."
But Pau, who were also thrashed in the opening round, soon hit back.
Flanker Sean Dougall scored their try and Colin Slade kicked two penalties to put the home side 11-7 up at the break.
Belleau brought the home side within a point with a second penalty.
But Toulon lost Swan Rebbadj to a yellow card and Slade kicked two more penalties for the home team and Tom Taylor a fifth to seal the victory.
Castres were trailing Lyon 16-3 at half-time but erased the deficit with two tries from centre Thomas Combezou and Rory Kockott's penalty sealed a hard-earned victory two minutes from time.
In front of a 12,000 crowd at the Stade Jean-Bouin in Paris, Stade Francais also trailed at half-time but they were a completely different team in the second half as Nayacalevu Waisea and Kylan Hamdaoui crossed and Jules Plisson converted both, adding to two penalties in the first half.
"We said to ourselves that we had to hang onto the ball and impose our game on them. We played more simply and we scored two great tries," Plisson said.