Police clash with hardliners as thousands hit Paris for May 1

Paris riot police fired teargas as they squared off against hardline demonstrators among tens of thousands of May Day protesters, who flooded the city Wednesday in a test for France's zero-tolerance policy on street violence.

Tensions were palpable as a heady mix of labour unionists, "yellow vest" demonstrators and anti-capitalists gathered in the French capital, putting security forces on high alert.

Ahead of the main march, the city was on lockdown with more than 7,400 police and gendarmes deployed with orders from President Emmanuel Macron to take an "extremely firm stance" if faced with violence.

Clashes briefly erupted on Montparnasse Boulevard, where hundreds of anti-capitalist "black bloc" activists pushed to the front of the gathering crowd, hurling bottles and other projectiles at police, who fired tear gas and stingball grenades, an AFP correspondent said.

Used at ground level, the grenades release scores of rubber pellets that cause an intense stinging to the ...