A small group of French protesters stormed through Paris overnight smashing the windows of shops and bus stations, leading Interior Minister Bernard Cazeneuve to declare Friday that the protesters promoting violence would be detained "tirelessly."
Police said some 300 people left the central Place de la Republique late Thursday, where nightly peaceful demonstrations have been held for weeks.
They made their way through the 10th and 19th neighbourhoods shortly after French President Francois Hollande appeared in a 2-hour televised debate during which he said a divisive labour reform package would not be withdrawn.
The group of protesters targeted an employment office, a supermarket, and a car-sharing service station. Television images showed broken windows and graffiti.
Largely peaceful demonstrations have been underway for weeks across France in protest against legislation put forward by Labour Minister Myriam El Khomri, which is widely seen as undermining hard-won labour rights like the 35-hour work week.
The bill would change rules governing how many hours a week employees can work, with additional rules on overtime compensation, and would change the conditions for payouts on unjust dismissal cases. It also takes aim at rules governing unions.
Decrying Thursday night's defacements as "intolerable," Cazeneuve said that, "those who are without ideals and who are only driven by an instinct to create violence will be tirelessly detained and pursued by the police forces."
Student demonstrations earlier on Thursday saw youth scuffling with police, who fired tear gas and wielded batons at a central train station and in the northern neighbourhood near Stalingrad plaza. Cazeneuve was quoted by AFP news agency saying that 151 police officers have been wounded in the protests.
Police said the group branched off from the Nuit Debout (Rise Up At Night) demonstrations that have been held for weeks in Republique.
Some demonstrators with the movement, which started as a protest against the labour reform and has become a broader protest against inequality, told BFM-TV broadcaster that the demonstrations wasn't associated with the violent acts.
During the televised debate on Thursday evening, watched by nearly 3.5 spectators, Hollande said that he understood the frustration driving the protests while trying to underscore gains made during the first four years of his five-year term.
Answering a question about the Nuit Debout demonstrations, Hollande said, "I find it legitimate that the youth - in relation to the world as it is, in relation to politics as they are - want to express themselves and want to have their say."