French riot police clashed with "yellow vest" protesters in central Paris on Saturday during the latest wave of demonstrations against high living costs which have shaken President Emmanuel Macron's authority.
Some 8,000 officers and 12 armoured vehicles have been deployed in Paris alone, and almost 90,000 in the country as a whole.
Hundreds of protesters were milling around the Arc de Triomphe monument, which was defaced with anti-Macron graffiti last Saturday when rioters also torched dozens of cars and looted shops in the worst rioting in Paris since May 1968.
His morning tweet came in the middle of UN climate talks in Poland, where almost 200 nations have gathered to agree on a universal rulebook to make good on the promises they signed up to in the 2015 Paris climate deal.
"We need to protect culture sites in Paris but also everywhere in France", Culture Minister Franck Riester told RTL radio.
The operators of landmarks like the Eiffel Tower and the Louvre and Orsay museums said they would be closed, along with operas, theatres, libraries and major department stores.
As a precaution, almost 300 people were arrested ahead of Saturday's expected disturbances, the report said.
The students were detained by police in the Paris suburb of Mantes-la-Jolie, in unrest that has spread to dozens of schools during three weeks of anti-government demonstrations.
Crowds had first tried to march down the Champs-Elysees avenue toward the Elysee Palace, but were prevented by rows of police pushing back with shields.
Macron on Wednesday agreed to abandon the fuel tax increase, but the protesters' anger at his government has not abated.
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Macron's decision early in his presidency to slash taxes on France's wealthiest is particularly unpopular with the protesters.
"At the national level, including Paris, we're at more than 700 detained with participation in the movement at 31,000 nationwide including 8,000 in Paris", he told France 2 television. The city subway system was shut down in the centre of town.
In a sign the concessions offered by the government may be starting to weaken support for the movement, two opinion polls showed a decline in popularity for the "yellow vests" on Friday.
An expected 8,000 police officers will be dispatched in the capital to counteract the potential "small minority" who have been "radicalized and fallen into violence and hate", the Interior Minister Christophe Castaner said at a press conference on Friday.
But the movement has no clear leaders, and past protests have attracted extremists who hurled projectiles at police.
Philippe on Friday evening met a delegation of self-described "moderate" yellow vests who urged people not to join the protests.
In the Dutch city of Rotterdam, a few hundred protesters in the high-visibility vests walked peacefully across the Erasmus Bridge singing and handing flowers to passers-by. "Some ultra-violent people want to take part".
Yellow Vest mayhem has hit the country for the 4th consecutive weekend.
Macron's "cardinal sin", in the eyes of the protesters, was slashing wealth taxes shortly after taking office.
Since the unrest began on November 17 in reaction to a sharp increase in diesel taxes, four people have been killed in violence related to the protests.
Paris police, fearing that radical protesters could turn street furniture and construction materials into makeshift weapons, on Friday were removing all glass containers, railings and construction machines in high-risk areas.