One of the country's two largest union federations, the CGT, was joined by smaller groupings in demonstrating opposition to the government's plans to seek 50 billion euros in spending cuts to finance tax breaks for businesses, which were approved in parliament this week.
Ahead of a march that was to start at the Place de la Bastille in Paris, CGT general secretary Thierry Lepaon said the government was more concerned about "saving 50 billion euros [than] in work and workers".
Lepaon hoped to pressure the government to use a meeting with business leaders and unions scheduled for July to focus on "the concerns of French people: salaries, jobs and financing social protection".
For the second year in a row, the CGT and its allies will not be joined by the other big French union federation, the CFDT, even though they marched together during the years of right-winger Nicolas Sarkozy's presidency.
Since the Socialists came to power in 2012, the two groupings have failed to find common ground on workplace and pension reforms and on the current cuts plan.
"We have no common objectives," CFDT general secretary Laurent Berger said on 18 April, adding that the CFDT and the CGT practiced "two kinds of unionism".
Instead the CFDT, along with one smaller union and guests from Belgian and Spanish unions, demonstrated for "Europe, jobs, social progress" in northern Paris, declaring that they hope to counter "populisms and the far right".
Also taking on a European theme was the far-right, anti-European Front National (FN), which held its own 1 May march in tribute of 15th-century Catholic Saint Joan of Arc, whom it considers a patriotic warrior symbolising its own values.
Seeking to capitalise on the results of last month's nationwide local elections that saw seven FN members become mayors, the party promised a "historic" show of force.
"We're in the process of losing our freedom, our security and our prosperity," said FN president Marine Le Pen. "We have to take them back and that will happen on 25 May, during the European elections."
On the sidelines of that march, small groups of anti-racist and anti-fascist demonstrators held a vigil in memory of a Moroccan immigrant who was thrown into the Seine river by three far-right demonstrators who had taken part in the Front National march of 1 May 1995.
Brahim Bouarram, a 29-year-old father of two children, was thrown from a bridge and, not knowing how to swim, drowned in the river.
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