PARIS (Reuters) - Tens of thousands of supporters of French presidential candidate Jean-Luc Melenchon marched on the Bastille on Sunday, bringing a revolutionary battle cry to an election campaign in which the hard-left is damaging Socialist favorite Francois Hollande's chances.
Melenchon's Left Front, a coalition of radical left parties including the Communists, has seen its support rise in the polls in recent weeks ahead of an April-May presidential election, eroding Hollande's voter base and pushing the mainstream Socialist into more radical territory.
Left Front officials said some 120,000 people had joined the peaceful march to hear Melenchon's call for a citizens' revolution, making it by far the biggest rally of the 2012 election campaign. Protestors brandished banners demanding a VIth republic, proclaiming a popular "thirst for justice".
"Spirit of the Bastille, we are back, the people of France's revolutions and rebellions," Melenchon said before a crowd of cheering supporters, stretching across Bastille square and into the surrounding streets.
"We are here today because we want to turn this election into a citizens' insurrection that will start at the ballot box and trigger the popular revolution we need to profoundly change the lives of a suffering people," he said.
The procession wound its way from Place de la Nation to Bastille, site of the eponymous former fortress and symbol of the despotic Bourbon monarchy, that was stormed in the 1789 Revolution.
Driving home the revolutionary message, supporters donned the red liberty caps of the 18th century revolt and the march was symbolically held on the anniversary of the 1871 Paris Commune uprising that followed the collapse of Napoleon III's Second Empire.
Turnout outstripped the initial estimates of 30,000 people, reflecting the radical left's growing impact in the presidential contest as disgruntled voters turn away from mainstream politics.
"We are the cry of the people, of the impoverished and abandoned workers," Melenchon said, wearing his trademark red tie as he urged people to take to the streets of towns and villages across France.
Further open air rallies are planned in Toulouse and Marseille in the coming weeks in an attempt to imitate the Commune revolt which spread from Paris to the two southern French towns.
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Graphic: French election polls r.reuters.com/was36s
Melenchon has been blazing a trail through the presidential campaign, doubling his support in the polls and chipping away at Socialist Hollande's lead, allowing conservative incumbent President Nicolas Sarkozy to narrow the gap between them.
The latest IFOP survey for Journal du Dimanche on Sunday showed Melenchon gaining 11 percent in the first round vote on April 22, up from 6 percent in January. It also showed Hollande slipping back to 27 from 28 percent, and gave Sarkozy the lead - in the first round vote alone - with 27.5 percent, up from 26 percent.
Polls show Hollande would still soundly beat Sarkozy in a second round runoff in May however.
Melenchon's calls for a 100 percent tax on salaries over 360,000 euros ($474,314) a year and a minimum monthly wage of 1,700 euros have struck a chord with angry voters, disillusioned by four years of crisis they attribute to the excesses of the rich.
One of his main strengths has been his ability to unite disparate radical factions who would otherwise have garnered only low single-digit scores in the vote. Bringing them together has lent the hard-left agenda greater weight in the campaign, pushing the political debate onto more radical ground.
Few for example consider it a coincidence that the moderate Hollande announced his off-the-cuff 75 percent tax rate on high earners just as Melenchon was approaching double figures in the polls.
Even Sarkozy has strayed into hard-left territory, pinching the Left Front's proposal to impose a levy on tax exiles and their pledge to give the people back its voice with referendums.
Melenchon is also turning heads with his eloquent rhetoric and talent for a soundbite, skills that have turned him into a darling of the media considered capable of pushing up TV ratings.
His resounding battle cry on Sunday, full of rhetorical flourishes and literary references, stole the media spotlight from Hollande who went on a tamer walkabout at a book fair and later outlined his agenda for culture at a meeting in Paris.
"I didn't see him, I don't think anyone saw him," Melenchon joked on France 2's evening news program, referring to the man he once called a "pedal boat captain".
Hollande was quick to dismiss Melenchon's rhetoric, saying he preferred to effect real change via an election rather than purely stir up people's anger.
"I don't want this election to be just an expression of legitimate anger, but rather a chance to change the country," he told reporters after his speech on culture.
Polls still indicate Melenchon has little chance of making it through to the second round of the presidential vote, however, as he trails both far right Marine Le Pen and centre-right Francois Bayrou.
His calls for a revolution could mobilize more supporters though and shake up the political debate.
"If we don't make it through the first round... then the question is what kind of left will we see in the second round," Melenchon told France 2.
Writing by Vicky Buffery; Editing by Andrew Osborn