Valls, who made these comments during a TV interview today, said that in most regions the political fight will be between the Republicans and the Left.
He reiterated that in regions where the National Front is likely to prevail, the Socialist Party will analyse the results after the first round and then do everything to prevent the victory of the extreme right party.
Valls said that the question is posed not only to the Left and the Socialist Party alone.
He said it can arise for the right as well, notably in the Nord-Pas-de-Calais - Picardie region.
The Prime Minister regretted and condemned the fact that a part of the Republicans was running behind the National Front on a number of topics. He however added that he does not confuse the Republicans with the National Front.
"We take our responsibilities because in these times, we must be selfless. Most importantly, it will prevent the anti-Semitic and racist extreme right to take a region. What I ask the Republican right is to take responsibility,” he said.
The December regional polls are crucial for all parties as they are the last test before the presidential election in 2017.
Though the Republicans are expecting a comfortable win, the National Front could emerge victorious in couple of regions – especially Nord-Pas-de-Calais-Picardie in the northeast where Le Pen is standing, and the party’s traditional stronghold in the southeast, Provence-Alpes-Cote-d'Azur.