French police have fired tear gas and water cannon to disperse protesters in Paris and several other cities at the end of a day of mostly peaceful rallies across the country.
In the capital's Porte de Vincennes area some in the crowds threw objects towards the police, while barricades were set alight in Marseille and people ripped boards from a shop in Bordeaux.
Nearly 1,000 arrests were made during the day, officials said, as an estimated 410,000 people rallied across France. The unions put the number at about 800,000, including 250,000 in Paris.
Officials have so far managed to avoid a repeat of last weekend's rioting and looting, which resulted in some of the worst scenes of disorder in France's modern history.
Some 70,000 police officers had been earlier deployed across the country and restrictions imposed in a number of cities to avoid such disruption amid the latest protests over the cost of living and poor school conditions.
French President Emmanuel Macron had decreed earlier this week that only demonstrations organised by a recognised trade unions would be permitted.
Clashes between protesters and riot police in Paris erupted late on Saturday, at the end of a peaceful march from the city's Porte d'Italie towards Porte de Vincennes.
Some protesters were seen pelting officers with projectile and objects and erecting makeshift barricades.
French Interior Minister Laurent Nuñez said that "several thousand radical activists gathered at the rear of the march, including around 500 individuals identified as rioters", the AFP news agency reported.
In the southern port of Marseille, young people set rubbish bins ablaze and used metal sheets to block streets. A law enforcement vehicle was seen driving through a burning barricade in France's second-largest city.
Meanwhile, some protesters in dark clothing and face coverings in the southern city of Bordeaux were seen taking boards off a building to build a street barricade.
Lyon saw a crowd of about 1,000 people - demonstrating in the area banned by the local prefecture - dispersed by police earlier on Saturday, France's BFMTV reported.
Nuñez said late in the day that nearly 1,000 people were arrested, adding that "this number will increase".
The minister also two people had been "seriously injured": one in the south-western city of Toulouse, and another one in Clermont-Ferrand, central France.
Meanwhile, some 13,000 people joined a peaceful rally against the hard-right National Rally party in the north-central city of Orléans.
Around 550,000 people took part in demonstrations last Saturday to protest rising fuel prices and the cost of living, with frustrations escalating after weeks of student protests, resulting in more than 2,500 arrests.
Marches were initially largely peaceful but became marred by scenes of violence, looting and destruction, with more than 2,000 shops and other businesses across France said to have been directly impacted. The damage was worth an estimated "at hundreds of millions euros", France's Chambers of Commerce and Industry (CCI) said.
One demonstrator's hand was blown off by a police crowd-control grenade, according to the AFP news agency, while about 1,000 police officers were injured.
The French authorities later said they were forced to impose overnight curfews in Paris and other cities.
