Paris police have fired tear gas on a group of yellow-vested protesters trying to march on the French presidential palace and have pushed them back with shields.
Crowds of protesters first tried to march down the Champs-Elysees avenue toward the Elysee palace but were prevented by rows of police.
So a group of a few hundred took side streets and tried to get past a police barricade, and police fired back with tear gas.
Most of the protesters remain peaceful, and there are no signs so far of the rioting and looting that marked a similar protest last Saturday and prompted fears of greater violence this week.
Crowds were also gathering across town around the Bastille plaza.
Authorities have detained 343 people on Saturday amid exceptional security measures.
Police are searching people throughout zones of central Paris and confiscating goggles and gas masks from journalists who use them to protect against tear gas while covering demonstrations.
Hundreds of people gathered early on Saturday around the Arc de Triomphe, which was damaged in rioting a week ago.
They then started walking peacefully down the avenue, lined with high-end shops normally bustling before the Christmas holidays but boarded up this Saturday amid worries of more looting or other damage.
President Emmanuel Macron's government is deploying 89,000 security forces around the country for Saturday's protests against his reforms.
Macron announced earlier this week that planned hikes in petrol and diesel taxes, which sparked the protest movement, would be cancelled.
But some protest leaders insisted rallies would go ahead over wider demands including tax cuts and salary rises.
The French yellow vest protest movement is crossing borders, with demonstrations planned in neighbouring Belgium and in the Netherlands.
Hundreds of police officers were mobilized in Brussels on Saturday, where yellow vest protesters last week clashed with police and torched two police vehicles. More than 70 people were detained.
Paris monuments and shopping meccas are locked down.
The Eiffel Tower and Louvre are shut along with hundreds of stores and businesses.
The protesters are angry at Macron and high taxes, among other problems.