French President Nicolas Sarkozy delivers a speech during a campaign rally in Saint Cyr Sur Loire on Monday - a day after the first round of presidential elections where he ended in second place behind the Socialist candidate.

Paris - French President Nicolas Sarkozy appealed directly to far right voters on Monday with pledges to get tough on immigration and security, after a record showing in a first round election by the National Front made them potential kingmakers.

Polls show centre-right leader Sarkozy on course to become the first French president to lose a bid for re-election in more than 30 years, trailing Socialist challenger Francois Hollande ahead of a May 6 run-off.

Hollande pipped Sarkozy in Sunday's 10-candidate first round by 28.6 percent to 27.2 percent, but National Front leader Marine Le Pen stole the show, surging to 17.9 percent, the biggest tally a far-right candidate has ever managed.

Her performance mirrored advances across the continent by anti-establishment Eurosceptical populists from Amsterdam and Vienna to Helsinki as the euro zone's grinding debt crisis deepens anger over government spending cuts and unemployment.

“National Front voters must be respected,” Sarkozy told reporters as he left his campaign headquarters in Paris. “They voiced their view. It was a vote of suffering, a crisis vote. Why insult them? I have heard Mr Hollande criticising them.”

The unpopular Sarkozy, the first sitting president to be forced into second place in the first round of a re-election bid, now faces a difficult balancing act to attract both the far-right and centrist voters he needs to stay in office.

The weak showing by Sarkozy spooked investors already nervous about European governments' ability to service their debts, helping to send French stocks and bonds lower.

Returning to the campaign trail on Monday, Sarkozy hammered home promises to toughen border controls, tighten security on the streets and keep industrial jobs in France - signature issues for Le Pen at a time of anger over immigration, violent crime and unemployment running at a 12-year high.

Sarkozy will hold a “real workers'“ day rally on May 1 in a bid to upstage simultaneous events held by Hollande, the FN and trade unions.

After five turbulent years leading the world's fifth economy, Sarkozy could go the way of 10 other euro zone leaders swept from office since the start of the crisis in late 2009.

Hollande has vowed to change the direction of Europe by tempering austerity measures with higher taxes on the rich and more social spending. Polls published on Sunday predicted he would win the run-off with between 53 and 56 percent of votes.

But the strong showing of Le Pen, gravel-voiced 43-year-old daughter of National Front founder Jean-Marie Le Pen, offered Sarkozy a glimmer of hope by suggesting there are more votes up for grabs on the right than had been thought.

“Marine Le Pen's breakthrough throws the second round wide open,” read the front page of right-leaning Le Figaro, while left-wing Liberation read: “Hollande leads. Le Pen the killjoy”.

Hollande blamed Sarkozy for fuelling the rise in the far right and said he would make no attempt to seek National Front votes. “Since some voters supported them out of anger, I will listen to them... but I will not court the far right,” he said.

On a strong turnout of 80.2 percent, more than a third of voters cast ballots for protest candidates outside the mainstream, foreshadowing a possible reshaping of France's political balance of power at parliamentary elections in June.

Le Pen's focus is now on securing a strong National Front showing in the parliamentary vote, and she is keeping her distance from Sarkozy, describing him as doomed.

“Faced with an outgoing president who will leave a much weakened party, we are the only true opposition to the neo-liberal left,” she told cheering supporters on Sunday.

She said she would give her view on the runoff at a May Day rally in Paris. Speaking on France 2 she said it was insulting to her voters to say they had chosen her in protest and suggested she would not formally endorse either candidate.

“I don't change my mind like I change my shirt,” she said. “I have nothing to sell or negotiate. For a long time I have considered Nicolas Sarkozy and Francois Hollande to be the same on core subjects.”

It is not the first time Sarkozy has appealed to National Front voters before a runoff - the tactic helped him win his first mandate in 2007. Le Pen's strategy director Florian Philippot said it would not work twice: “The French no longer fall for this electioneering game Sarkozy plays.”

Financial market analysts say whoever wins in two weeks' time will have to impose tougher austerity measures than either candidate has admitted during the campaign, cutting public spending as well as raising taxes to cut the budget deficit. - Reuters