France's President Sarkozy and Prime Minister Fillon shake hands at the Elysee Palace in Paris. (Philippe Wojazer/Reuters)

French President Nicolas Sarkozy plotted strategy with his prime minister Monday after their conservative party's crushing defeat in regional elections, with a cabinet shuffle said to be in the offing.

Sunday's vote informally kicked off the 2012 presidential race, delivering a wake-up call to Sarkozy to change tack on jobs and other economic policies and reconnect with alienated voters if he wants to win a second term.

Prime Minister Francois Fillon met for 80 minutes with Sarkozy at the presidential palace with speculation widespread about who was likely to go in a cabinet shakeup. Earlier, Sarkozy's chief of staff predicted a modest post-election reshuffle.

Presidential security guards closed off the Elysee Palace to reporters. As Fillon left, former interior minister Francois Baroin — a fellow conservative and long an ally of former president Jacques Chirac — arrived to meet with Sarkozy.

"These elections show that the French are worried," Fillon said. Fillon blamed the recession for his party's bad showing, but warned that France can no longer finance its generous social benefits without cost-cutting, and suggested reforms would continue.

The long-flailing French left made a big-time comeback in the vote, which was coloured by worries about jobs, paycheques and pensions in the wake of France's worst recession since the Second World War. The extreme right also bounced back from decline and proved that worries about immigration and France' evolving national identity remain alive.

Cheers resounded from Socialist Party headquarters as leftists swept races from the French Riviera to Paris. With 99.6 per cent of ballots counted, the Socialists and their allies won 53.8 per cent of the vote nationwide, while Sarkozy's UMP (Union for A Popular Movement) party had 35.5 per cent, according to the Interior Ministry.

The far right National Front reversed its decline and won 9.5 per cent of votes overall in the 12 regions where they made it into Sunday's runoff — and in some regions topped 20 per cent.

Voter turnout, though, hit record lows in Sunday's runoff — at 51 per cent — and in the first round a week earlier, when it was just 46 per cent.

Sunday's elections decided the leadership of 26 regional councils from the French mainland to far-flung provinces in the Caribbean and the Indian Ocean.