Anti-government protests in France have “created a monster”, France’s Interior Minister Christophe Castaner has said.
And he is warning that “radical elements” could infiltrate planned “yellow vest” protests at the weekend.
Tourist sites in Paris are to close on Saturday amid fears of further street violence.
The protests began three weeks ago, initially against a rise in fuel taxes but have spread to take in other issues, including education reforms.
Mr Castaner said “large-scale security measures” would be put in place this weekend.
Across France, 89,000 police officers will be on duty and armoured vehicles will be deployed in the capital, Prime Minister Edouard Philippe announced.
Paris police have urged shops and restaurants on the Champs-Elysees to shut and some museums will also be closed.
The government has said it is scrapping the unpopular fuel tax increases in its budget – but discontent with the government has spread and protests have erupted over other issues.
Further protests have been reported in the east of country.
One student has been injured following a demonstration in the town of Montbéliard, about 13km from the border with Switzerland, local media report. A police officer was seriously injured at a student protest in Mulhouse, according to French broadcaster BFMTV.
The AFP news agency reports that authorities seized 28 Molotov cocktails and 3 homemade bombs from “yellow vest” protesters in the south of the country.
There has also been widespread anger at images showing how police made high school students kneel and put their hands behind their heads following clashes on Thursday in Mantes-la-Jolie, to the west of Paris.