May Day riots rock Paris as more than 100 detained by police

Emmanuel Macron says he 'very much condemned' the violence

More than 100 people are in custody after rioters smashed windows and torched cars during May Day protests in France.

A total of 1,200 masked and hooded protesters from the far-left anarchist group, the Black Blocs, hijacked what was intended to be a peaceful rally against public sector labour reforms.

Four people, including one police officer, were injured as rioters dressed in all black smashed windows, torched cars and also hurled petrol bombs after a call on social media for a “revolutionary day”.

The police had to use water cannons and teargas against the masked protestors in an effort to disperse the crowds.

Government spokesman Benjamin Griveaux condemned those who took to the streets.

“When you have sincere convictions, you demonstrate with your face unmasked,” Mr Griveaux said.

“Those who wear hoods are the enemies of democracy.”

Emmanuel Macron condemned the violence but said his government was not overly worried about the incidents.

The president, speaking through an interpreter at a media conference on a visit to Australia, said he "very much condemned" the violence.

"The first of May is an international celebration. It is the day when we celebrate workers, not rioters,” he said.

"Some arrests have been made and all necessary measures were taken.

"We shall not be too concerned about it. We shall stand firm. There is a government, there is a state, there are leaders, and it will continue to be so."

Agencies contributed to this report