More than a 100,000 people took part in May Day demonstrations throughout France on Saturday.
Some 170,000 people turned out nationwide, according to the CGT trade union. Some 25,000 were in Paris.
The Interior Ministry said 106,000 people had attended rallies, with 17,000 in Paris.
The marches to mark International Workers' Day were mostly peaceful.
There were isolated incidents in Paris and Lyon, as police clashed with members of the far-left "black bloc" group and used tear gas.
The CGT said that 21 people were injured, including four seriously, at the very end of the Paris demonstration.
Some 56 people were temporarily taken into police custody, 46 of whom in Paris, French news agency AFP reported, citing the Interior Ministry.