The National Front, which stages a procession through the French capital on May 1 every year to celebrate folk heroine Joan of Arc, is currently doing well in opinion polls on the back of the economic crisis and a deeply unpopular government.
Party leader Marine Le Pen, a fervent critic of the European Union, said France had "shut itself away in the darkness of Europe" in a speech after the march in front of Paris's famed opera building, on top of which fluttered a EU flag.
France "is sinking into an absurd policy of endless austerity... because it's about always saying yes to Brussels, to Berlin of course, and to financial moguls in all circumstances," she said.
Le Pen's speech to hundreds of supporters carrying French flags comes as the National Front is gaining strength just as Socialist leader François Hollande's government struggles against a tide of discontent.
In one recent opinion poll, when asked who respondents would vote for if an election was called immediately, former president Nicolas Sarkozy came first and Le Pen second, far ahead of Hollande in third.
His government has been affected by stagnant growth, high unemployment and a scandal involving ex-budget minister Jerome Cahuzac who was charged with tax fraud for siphoning hundreds of thousands of euros into a secret foreign bank account.
Since his election last May 6, Hollande's approval rating has fallen faster and further than any other president's since the founding of France's Fifth Republic in 1958.
As a result, the National Front says it has gained more followers, including Socialists unhappy with their government, though they have not provided any figures.
Story continues below…
David Assouline, spokesman for the Socialist party, hit out at Le Pen's speech, warning people not to be taken in.
"Behind lofty, misleading comments against bankers, she only becomes concrete when it's about attacking unions and immigrants," he said in a statement.
The far-right party is looking to municipal elections next year, where it hopes to gain control of several towns or cities.