Image caption Mr Sarkozy has been in politics for decades

Nicolas Sarkozy has said he will give up politics if he fails to be re-elected president of France at the election this spring.

Opinion polls suggest he is lagging behind Socialist challenger Francois Hollande, who is expected to face him in a second round run-off on 6 May.

Critics accuse Mr Sarkozy of competing for votes with the far right by saying France has too many foreigners.

National Front hopeful Marine Le Pen is struggling to qualify for the election.

Mr Sarkozy, 57, is coming to the end of his first term as president, before which he served as a cabinet minister under his predecessor, President Jacques Chirac.

His political career stretches back to the early 1980s when he served as a district mayor in Paris.

Speaking to French broadcaster BFMTV on Thursday, Mr Sarkozy said "I tell you, yes" when asked whether he would quit politics if defeated.

I'm looking but having trouble finding them [endorsements from elected officials] Marine Le Pen, National Front leader

Mr Sarkozy stirred controversy this week by saying in a TV debate that there were too many foreigners in France and the system for integrating them was "working worse and worse".

He promised to reduce the number of immigrants to France from 180,000 a year to 100,000 if re-elected.

Mr Sarkozy, who is himself the son of a Hungarian immigrant, also said he wanted to restrict some benefit payments to immigrants who had been in the country for 10 years.

'Thirty short'

Earlier, he promised to review the endorsement system for candidates if re-elected.

Candidates need to be endorsed by at least 500 of France's elected representatives by a deadline of 16 March in order to stand.

Ms Le Pen said on Thursday she was "about 30" short and had six working days to reach the requirement. "I'm looking but having trouble finding them," she said, adding that 27 mayors had withdrawn their support.

Opinion polls suggest she would come third in the first round of the election but correspondents say many elected officials are reluctant to identify publicly with the far right.

By contrast, two candidates with just a fraction of Ms Le Pen's support in opinion polls, Jacques Cheminade, 70, and leftist Nathalie Artaud, secured their 500 endorsements in the past two days.

The first round of the election is due to take place on 22 April.

Photo row

Asked by reporters on Thursday, Mr Hollande said he did not intend to leave politics should he lose the election.

Image caption Paris Match defended its feature

In another development, his partner, journalist Valerie Trierweiler, reacted angrily to a decision by Paris Match magazine, for which she works, to splash a photo of the couple on its front page.

"What a shock to find yourself on the front page of your own paper," she said in a message on the micro-blogging site Twitter.

"Angry to see the use of photos without my agreement and not even being warned in advance."

The magazine's headline ran: "Francois Hollande's charming asset. The story of how their love was born."

Trierweiler later tweeted: "Bravo to Paris Match for its sexism on International Women's Day. My thoughts go out to all angry women."

However, the magazine tweeted back with equal sarcasm: "It's true, Valerie. We didn't discuss the front page with you. That's Match's independence. You are best placed to understand that."