The annual May Day event was held this year as polls show increased backing for the anti-immigration party, France 24 reported.
National Front (FN) leader Marine Le Pen promised marchers she would be "the light of hope" for French people as they deal with the "darkness" brought by the financial crisis.
A poll published Tuesday found FN would garner 23 percent of the vote if presidential elections were held Sunday. While that's far ahead of President Francois Hollande's 19 percent, it's still behind the 34 percent of former President Nicolas Sarkozy.
Hollande's popularity has fallen as unemployment in the country has risen to record levels and France has been split over social issues such as the legalization of gay marriage.
Recent labor reforms have spread the discord to the ranks of labor unions, Radio France Internationale reported.
During Sarkozy's time in office, the May 1 celebrations saw members of the various unions march together in opposition to his policies. This year, the politically powerful left wing CGT union, which opposes a recently adopted law aimed at giving the labor marker more flexibility, organized 279 separate marches with other left-wing unions.
The more moderate CFDT union, which supported the law, held its own marches.