PARIS (AP) -- The stunning arrest of IMF chief Dominique Strauss-Kahn in connection with a sexual assault in New York is throwing the French presidential race into disarray.

Some rivals and political observers said it could bury any presidential bid by Strauss-Kahn, considered the strongest potential challenger to unseat the unpopular President Nicolas Sarkozy in next year's election.

Others urged caution pending further investigation into the alleged assault by Strauss-Kahn, an accomplished politician and economist who has been in the French public eye for decades. A few even suggested that Strauss-Kahn may have been set up.

The arrest also shook up talks that Strauss-Kahn was having in Europe this week about the euro currency crisis and more aid to debt-laden Greece.

Strauss-Kahn is facing arraignment on charges of attempted rape and a criminal sex act involving a maid in a New York hotel. He was whisked off an Air France plane amid the police investigation.

Strauss-Kahn has not announced his candidacy for France's presidency, but was widely expected to seek the Socialist Party nomination to run against the conservative Sarkozy.

The IMF chief has for months led polls of presidential contenders. A poll by the IFOP agency published this weekend showed Strauss-Kahn with the highest support among possible presidential candidates, trailed closest by Sarkozy and far-right leader Marine Le Pen.

Le Pen, who heads the National Front party, said Sunday that Strauss-Kahn has been ``definitively discredited as a candidate.''

Sarkozy himself did not comment publicly Sunday, nor did his aides. The president's popularity has been in the doldrums for months. Voters on the left and within his conservative party are frustrated by Sarkozy's hardline stance on immigrants and his failure to fulfill many promises he made to boost France's economy.

Socialist Party chief Martine Aubry _ who harbors presidential ambitions of her own _ said the news of Strauss-Kahn's arrest hit her ``like a thunderbolt. I am, like everyone, stupefied.''

She called on the long-divided Socialist Party to ``remain united and responsible'' pending further developments.

``I think his political career is over,'' Philippe Martinat, who wrote a book called ``DSK-Sarkozy: The Duel'' about the two political rivals, told The Associated Press. ``Behind him he has other affairs... I don't see very well how he can pick himself back up.''

Strauss-Kahn is known in France as ``DSK'' for his initials, but French media have also dubbed him ``the great seducer.'' His reputation as a charmer of women has not hurt his career in France, where politicians' private lives traditionally come under less scrutiny than in the United States.

A married father of four, Strauss-Kahn was briefly investigated in 2008 over whether he had an improper relationship with a subordinate female employee. The IMF board found his actions ``regrettable'' and said they ``reflected a serious error of judgment,'' but the relationship was deemed consensual.

``(Seducing women) was Dominique Strauss-Kahn's Achilles heel. We knew he had a fragility in this sense,'' said Martinat.

Segolene Royal, who beat out Strauss-Kahn for the Socialist nomination in 2007 elections and is considering another bid, urged caution in judging her rival.

``Dominique Strauss-Kahn has the right, like everybody, to the presumption of innocence,'' she told the AP in Paris on Sunday. ``We have to allow justice to do its work in complete serenity. My thoughts go to the man in this difficult time and to his family.''

Strauss-Kahn ally Jean-Marie Le Guen recently suggested the IMF chief was the subject of a smear campaign when pictures of the IMF leader in a Porsche were circulating in French media, and defended him on Sunday.

``The facts as they were reported today have nothing to do with the Dominique Strauss-Kahn whom we know,'' he said on France's BFM television.

Jerome Fourquet of the IFOP polling agency said the incident could help former Socialist Party boss Francois Hollande, who has been gaining in the polls.

``People are going to try to understand, explain, even write it off _ some have already suggested it was a plot,'' Fourquet said. ``If he's cleared, he could return _ but if he is let off only after four or five months, he won't be able to run'' because the presidential campaign will be too far along.

``Media-wise, symbolically, he's almost automatically out of the game for now,'' he said.

Fourquet said supporters of Sarkozy ``are going to be quietly gleeful _ but they're going to be very careful'' in public.

Regardless of the outcome, ``it's a catastrophe for the image of our country,'' Fourquet said.