They retained control of Paris, with their candidate Anne Hidalgo.
France’s governing Socialists have suffered big losses in municipal elections, with the opposition UMP claiming victory and the far right celebrating further gains, the BBC reports.
UMP leader Jean-Francois Cope hailed what he called a “blue wave” of support for his centre-right party.
The far-right National Front (FN) was heading for victory in up to 15 towns, partial results indicated.
The Socialists have been hit by growing discontent over the economy.
Prime Minister Jean-Marc Ayrault acknowledged the vote was “a defeat for the government and the [Socialist] majority”. “This message is clear… The president will draw conclusions, and he will do so in the interest of France,’’ he added, in an apparent reference to a likely cabinet reshuffle.
The Socialists were said to have lost 155 towns of more than 9,000 inhabitants, Mr Valls said late on Sunday.
Marine Le Pen’s National Front won control of 11 towns of more than 9,000 inhabitants, including the southern towns of Beziers and Frejus and Villers-Cotterets, north-east of Paris. The centre-right UMP was said to have captured a number of key cities, including Toulouse, Quimper, Limoges, Saint-Etienne, Reims, Roubaix and Tourcoing.
The Socialists retained control of Paris, with their candidate Anne Hidalgo due to become the capital’s first female mayor.
“I am the first woman to be mayor of Paris,” she said.