* Partial results show FN in first place with 26 pct
* Record low score for Hollande's Socialists
* Le Pen says "people have spoken" against Brussels (Updates with provisional results)
By Mark John and Leila Abboud
PARIS, May 25 (Reuters) - Marine Le Pen's far-right National Front stunned France's political elite on Sunday by taking first place in European Parliament elections, with President Francois Hollande's Socialists beaten into a poor third, provisional results showed.
It was the first time the anti-immigrant, anti-EU party had won a nationwide election in its four-decade history. If the results are confirmed, it could secure as many as 25 seats in the new European Parliament, more than eight times the three it won in 2009.
"The people have spoken loud and clear," a triumphant Le Pen told cheering supporters at party headquarters in a northwestern suburb of Paris.
"They no longer want to be led by those outside our borders, by EU commissioners and technocrats who are unelected. They want to be protected from globalization and take back the reins of their destiny," she said.
France was a founding member of the European Union but voters have grown increasingly disenchanted with its free-market and open-border policies in recent years, rejecting a proposed EU constitution in a 2005 referendum.
Partial results released by the Interior Ministry gave the FN 26 percent, even higher than expected in pre-vote polls.
The party has carved out a niche in French politics, notably among disaffected working class voters who believe the mainstream elite does not understand their concerns about crime, immigration, job losses and stagnant living standards.
The mainstream UMP conservative opposition came second with 20.66 percent. Hollande's Socialists took just 13.88 percent, well down from the 16.5 percent they won last time in 2009 and worse than their previous low of 14.5 percent in 1994.
The FN, which Le Pen has sought to rid of its racist reputation since she took the reins from her father in 2011, campaigned on a platform of tighter borders, hostility to the euro currency and rejection of a planned EU-US trade pact.
"It's an earthquake," said Prime Minister Manuel Valls, brought in by Hollande barely two months ago after the Socialists suffered a similar rout in local elections.
"We are in a crisis of confidence ... Europe has disappointed - that's a fact," Valls said.
He urged the 28-member bloc to give more priority to social justice and pledged his government would pursue efforts to revive the euro zone's number two economy, which saw zero growth in the first quarter, by easing the tax burden on business.
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Le Pen called for the dissolution of parliament, insisting it was no longer representative of the French people's will. The FN holds only two of 577 seats in the National Assembly.
The Socialists quickly dismissed such a move which, given Hollande's record unpopularity, would almost certainly mean that his allies would lose their majority. The next presidential and parliamentary elections are not due until 2017.
The score was also a blow to the conservative UMP, whose chairman Jean-Francois Cope is expected to face challenges to his leadership.
"It's a big disappointment for us, but mostly an expression of anger from the French people," Cope said.
The Interior Ministry put turnout at just over 43 percent, a few points higher than it was at the last EU election in 2009.
In March the FN won control of 11 town halls - a tiny minority of France's thousands of municipalities but still a slap in the face for the mainstream left and right which have always ruled.
Le Pen told Reuters in the run-up to the vote that a major priority for the FN and other Eurosceptic parties across Europe would be to form a political caucus in the European Parliament and to block a planned transatlantic trade pact. (Editing by Mike Peacock and Paul Taylor)