Marseille rejoined Ligue 1 leaders Paris Saint-Germain and Lyon on 38 points with a 1-0 win over St Etienne on Sunday.
superbly headed home Rod Fanni's cross on the stroke of half-time to earn Marseille a fourth victory in their last five league matches.
St Etienne, in contrast, have now earned just two points from their last five matches and have gone from looking like genuine title contenders to a side stuck in mid-table, 11 points adrift of the pacesetters.
Valenciennes. meanwhile, bounced back from successive defeats with a hard-fought 2-1 win over 10-man Evian.
Goals from Gregory Pujol and Jose Saez saw the hosts to a victory that means they will spend the winter break inside the top six.
Saber Khelifa equalised for Evian in the first half but they had no response to Valenciennes' second goal, which came just moments after the visitors had lost Djakaridja Kone to a 71st-minute red card.
In Sunday's other game, Sochaux lost 2-0 at Toulouse to remain stuck in the bottom three heading into the winter break.
Adrien Regattin put the hosts in front in the first half with a superb free-kick and Emmanuel Riviere sealed the win five minutes from time.