PARIS (Reuters) - Demonstrators took to the streets of Paris and a clutch of French cities late on Sunday in protest at the shock triumph of far-right leader Jean-Marie Le Pen in the first round of presidential elections. Reuters correspondents said up to 10,000 protesters, many of them young leftists, filled the boulevard linking Place de la Bastille and Place de la Republique in the capital after Le Pen won through to a May 5 runoff against President Jacques Chirac. About 2,000 demonstrators sat on the cobblestones in Place de la Concorde, banging litter bins like drums and holding banners that read: "Le Pen. Shame." Marchers also massed in Lille, Lyon, Bordeaux, Grenoble and Strasbourg, where about 4,000 demonstrators shouted "Le Pen, you're finished. The French are on the streets" and "Fascism shall not pass." There were no immediate reports of disturbances. In Paris, police said they had blocked a group of protestors who were trying to march on the Elysee presidential palace. Le Pen, the 73-year-old leader of the anti-immigrant, anti-Europe National Front party, pushed Socialist Prime Minister Lionel Jospin into third place in the contest. Jospin announced on Sunday that he would quit politics after the runoff, which polling institutes now forecast Chirac, a conservative, will win by a landslide. Several of the demonstrations played on corruption allegations that have swirled around Chirac. "Vote sleaze, not fascist," protestors shouted in the northern city of Lille. Le Pen, who once called the Holocaust a detail of history, played down some of his more extreme rhetoric during the campaign, which he focused on law and order in a response to widespread public concern over rising crime. He dismissed the fascist label some of his opponents have given him in remarks on French television. "I have nothing to do with fascism," Le Pen said. "Fascism is protesting the result of a vote violently in the street."