The far right National Front could redraw the French political map by capturing five or six town halls in the second round of local elections this weekend.

As the dust settled yesterday after Sunday’s first round poll, French political commentators spoke of an “earthquake” and a “clap of thunder”.

Two years after he won the presidential election, President François Hollande’s Socialists suffered a series of humiliating reverses and Marine Le Pen’s National Front took significant steps towards the banality and respectability that she craves.

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The far-right party – Europhobic, protectionist, anti-establishment, anti-immigrant, pro-Russian – posted its best-ever results in a French local election. The National Front won one town outright – Hénin-Beaumont in the depressed, industrial north. It has strong chances of capturing Perpignan, Fréjus, Béziers and two or three smaller towns in the South this Sunday.

Although the NF scored only six per cent of the vote nationwide, it polled well enough to fight the second round of municipal elections in almost 200 towns – including many places in the western part of the country previously allergic to the Far Right. Ms Le Pen said that the results vindicated her efforts in the last three years to “de-demonise” the party. The National Front, she said, was now ready to govern,

This remains to be seen. The last time that the NF won three town halls, in 1995, the party proved to be too flaky and too ideologically driven to manage sensibly. The victories led to a series of embarrassments and legal challenges and, eventually, a split in the party.

The first round of the municipal elections also exposed the NF’s uneven strength across France and its shortage of credible candidates, especially in the largest cities. The party took only six per cent of the vote in Paris and failed to come near to winning any town larger than Avignon (pop 90,000).

Sunday’s results were, nonetheless, a severe blow for Mr Hollande who campaigned two years ago on a promise to “pacify” France and repair the social and economic fractures on which the NF thrives. His low polling ratings and failure to reverse the tide of unemployment made a poor result inevitable but Socialist barons had hoped for a relatively painless surrender of a few dozen towns to the centre-right. The surge in far-right support and a collapse in the left-wing vote in some towns left Mr Hollande looking more fragile than ever.

The respected centre-left newspaper Le Monde said that the President had suffered a calamity comparable to 21 April 2002 when the Socialist Prime Minister Lionel Jospin was beaten out of the second round of the presidential election by Marine Le Pen’s father, Jean-Marie. This is perhaps exaggerated.

The Left looks likely to hold onto the Paris town hall this weekend and will almost certainly retain other large towns, such as Lyon, Lille, Nantes, Rennes and Dijon. It finished an embarrassing third, behind the NF, in Marseille and will probably lose Toulouse, Caen, Amiens and Strasbourg.

The first round results in Paris gave a knife-edge lead to the centre-right challenger, Natalie Kosciusko-Morizet. The complexities of the Paris electoral system, and the wider vote for the Greens and hard left, means that the Socialist candidate, and present deputy mayor, Anne Hidalgo, will probably triumph next Sunday.

Socialist leaders said that the reverses would not alter Mr Hollande’s plans for public spending cuts and market-oriented economic reforms. Since these will bring pain before pleasure, the electoral outlook for the French Left as it approaches the 2017 presidential election is grim.

The Socialists – and the entire French political system – can expect another electroshock in May when the National Front is tipped to top the poll in the European Elections. President Hollande may go ahead with a long-rumoured government reshuffle next week or wait until this second electoral disaster is out of the way.

The far-right surge, though uneven across the country, also poses serious problems for the French centre-right. The main centre-right party, the Union pour un Mouvement Populaire (UMP) looks likely to win over 50 big or medium town halls from the Left in the second round this weekend. Its principal leaders did well on Sunday despite the financial scandals which have struck a series of UMP personalities, including the former President Nicolas Sarkozy.

All the same, the success of the NF may deny the centre-right the kind of sweeping local election gains which the Left won against an unpopular President Sarkozy in 2008. Despite the harder NF-like rhetoric of many centre-right candidates on social issues and immigration, the UMP has been unable to stop Ms Le Pen’s steady advance into both centre-right and left-wing electoral territory.

The UMP leadership has brushed away calls from the Left for a “Republican pact” this weekend in which the two mainstream political “families” would vote tactically to prevent the NF from capturing town halls. The UMP argues that such a pact would play into the hands of Marine Le Pen, who presents herself as the only opponent of the pro-European, pro-migration, pro-free-trade “system”.

The alternative Sarkozy strategy – stealing the clothes of the NF – has not helped the UMP much either.