Paris police have fired water cannon and tear gas to push back "yellow vest" demonstrators from around the Arc de Triomphe monument, in the ninth straight weekend of protests against French President Emmanuel Macron's economic reforms.

Thousands of protesters in Paris marched noisily but mostly peacefully through the Grands Boulevards shopping area in northern Paris, close to where a massive gas explosion in a bakery killed two firefighters and a Spanish tourist and injured nearly 50 people early on Saturday.

But small groups of demonstrators broke away from the designated route and threw bottles and other projectiles at the police.

Around the 19th-century Arc de Triomphe at the top of the Champs Elysees boulevard, riot police fired water cannon and tear gas at militant protesters after being pelted with stones and paint, witnesses said.

Groups of protesters also gathered on and around the Champs Elysees, the scene of disturbances in recent weeks, many of them calling loudly for Macron to resign.

"Macron, we are going to tear down your place!" one banner read.

The Interior Ministry estimated that there were a maximum of about 84,000 demonstrators nationwide on Saturday - more than the 50,000 counted last week but well below the record 282,000 estimated on November 17, the first day of the protests.

Much of central Paris was in lockdown on the first week of post-Christmas sales, with bridges across the Seine river closed and official buildings such as parliament and the Elysee presidential palace protected by police barriers.

In Paris, 156 "gilets jaunes" (yellow vest) protesters were arrested, some for carrying objects that could be used as weapons, police said. Nationwide, 244 people had been arrested, of which 201 remained in custody.

There were also thousands of marchers in the cities of Bordeaux and Toulon in southern France as well as Strasbourg in the east and the central city of Bourges.

More than 80,000 police were on duty for the protests nationwide, including 5000 in Paris.

The "yellow vests" take their name from the high-visibility jackets they wear.

Their rage stems from a squeeze on household incomes and a belief that Macron, a former investment banker seen as close to big business, is indifferent to their hardships.

Macron, often criticised for a monarchical manner, is to launch a national debate on January 15 to try to mollify the yellow vest protest, which has shaken his administration.