Dozens of demonstrators were arrested at yellow vest protests in Paris on Saturday as more than 7,000 police were deployed to quell any violence by the movement and its radical, anarchist "black blocs".

A man falls between French policemen during an anti-government demonstration called by the "yellow vest" (gilets jaunes) movement, on September 21, 2019 in Paris. (Photo: AFP)

There were also fears that the demonstrators could try to infiltrate a march against climate change in the French capital.

The yellow vest movement erupted 10 months ago and blindsided President Emmanuel Macron, whom protesters accused of being out of touch with the needs of ordinary French people.

Their weekly demonstrations prompted Macron to loosen the state's purse strings to the tune of nearly 17 billion euros ($18.8 billion) in wage boosts and tax cuts for low earners, but tapered off over the summer.

However, it remains to be seen whether the movement will regain the momentum of the winter and early spring, when the protests often descended into violent clashes with security forces, especially in Paris.

Several hundred protesters were in the streets of the French capital around 11am (0900 GMT) on Saturday.

By then police had arrested 39 of them, police headquarters said, adding that some protesters had been found to carry hammers or petrol canisters.

Macron on Friday called for "calm", saying that while "it's good that people express themselves", they should not disrupt a climate protest and cultural events also due to go ahead on Saturday.

The number of police deployed for Saturday's rallies are on a par with the peak of the yellow vest protests in December and March.