Oyonnax stunned Clermont Auvergne at the Stade Marcel-Michelin and Toulon capitalised by winning away in Grenoble.
Toulon once again find themselves at the top of the French domestic league thanks to a five-try win over Brive.
Bordeaux came back from an 11-point deficit to defeat Toulon 28-23 in the Top 14 at the Stade Chaban Delmas.
Newcastle, Exeter, London Irish, Cardiff and Connacht recorded bonus-point wins in the Challenge Cup.
Jake White's first game in charge of Montpellier ended in a win over Toulon, while Stade Francais hung on to top spot.
Stade Francais shocked defending champions Toulon 30-6 to end the year at the summit of the Top 14.
Wins for Toulon and Clermont at the weekend has kept the race for top spot alive in France's Top 14.
Stade Francais took over the leadership of the French Top 14 on Friday with a five-try 43-30 victory at Grenoble.
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