Police in France's capital, Paris, say that 109 people are in custody after the annual May Day protests turned violent.
The announcement on Wednesday corrected an earlier figure of 209 given by Interior Minister Gerard Collomb.
Police said that an estimated 1,200 masked and hooded youths dressed in black burned a McDonald's restaurant, smashed shop windows and torched several vehicles at Tuesday's rally, which was held by labour unions fighting for better worker and immigrant rights.
They chanted anti-fascist slogans and waved anti-government banners.
French trade unions and left-wing groups are currently protesting President Emmanuel Macron's proposals to loosen labour protections.
Collomb said 1,500 officers were deployed on Tuesday evening to protect buildings, and police used water cannon and tear gas against the youth.
He also vowed that France will increase police numbers for future protests.
"For the next demonstrations, there will be even more security forces, this time with the intention of totally separating protesters from those who have come to smash things up," he told France 2 television.
Macron, on a visit to Australia, said on Twitter he "firmly" condemned "the violence of the rogue demonstrations".
"We will do everything so that the perpetrators are identified and made responsible for their actions."
The mayor of Paris, Anne Hidalgo, also weighed in. She tweeted: "Their only purpose was to sow chaos. It's horrible. All my solidarity with the store owners and residents affected as well as the demonstrators who paraded quietly for the #1May."
Each year, people across the globe take to the streets to commemorate International Workers' Day, or May Day.
In dozens of countries, May 1 is an official holiday, and for labour rights campaigners it is particularly important.