The demonstrations are the fourth in a series launched in September that have done little to dent President Emmanuel Macron's ambitions of economic reforms, given his hefty majority in parliament.
Protestors across France came out on Thursday against President Emmanuel Macron's economic reforms, but low turnout suggested that resistance to an agenda seen as too pro-business was losing steam.
The demonstrations are the fourth in a series launched in September that have done little to dent the president's ambitions, given his hefty majority in parliament.
"Macron and the bosses are waging a social war, let's plan the counterattack", read a banner of the far-left Lutte Ouvriere (Workers' Struggle) party in Paris, where about 8,000 people turned out, according to police. That compared with about 200,000 who participated in a September 12 protest.
The Force Ouvriere union, one of France's largest, backed the demos for the first time, having previously shown a wait-and-see attitude toward the centrist Macron government.
Macron claims to have a mandate for change after handily winning the presidency in May and leading his centrist Republic on the Move party to a sweeping victory in the June parliamentary elections.
Police in Nantes fired tear gas to disperse crowds.
A major student union also took part, with some students angry over proposed reforms to the university admissions process.
Workers' rights trampled?
The government says its overhaul of labour laws is necessary to lower unemployment, which is stuck at around 9.6 percent —about twice that of Britain or Germany — but opponents accuse Macron of trampling on cherished workers' rights.
The strikes and street protests sparked by the labour reforms paled in comparison with those that have thwarted similar attempts by Macron's predecessors.
Nearly 400,000 turned out against president Francois Hollande in March 2016 at the height of protests against his reform efforts.
Additional sensitive changes — of the unemployment benefits system and pensions — are on Macron's frenetic agenda.
The new measures, some of which are already being pushed through by executive order, aim to make it easier for French firms to hire and fire employees and reduce the power of national collective bargaining.
Macron "has the upper hand"
In the southern city of Marseille, the radical-left firebrand Jean-Luc Melenchon said "thousands, millions of political activists... are ready to spring into action."
But even Melenchon, head of the France Insoumise (France Unbowed) party, acknowledged recently that Macron "has the upper hand, for now".
Protests were also held in dozens of other cities including Lyon, Nantes, Bordeaux and Strasbourg.