PARIS: Clashes between police and protesters, massive looting and multiple blazes gripped France on Saturday, as nationwide marches against soaring inflation degenerated into street violence of "extreme intensity."

The widespread unrest follows weeks of student protests and deepens political uncertainty as the country readies for elections in six months' time to replace President Emmanuel Macron.

Whole streets in Paris "have been devastated", the city's mayor, Emmanuel Gregoire, said as groups of masked young men torched parked cars and ransacked many shops.

French Prime Minister Sebastien Lecornu, who earlier slammed the "violence of extreme intensity", said late Saturday that 1,200 people had been arrested and 150 police officers hurt.