Video filmed by Reuters showed police dragging and beating a protester on the ground as protesters advanced and rebutted with projectiles and firecrackers amid tear gas smoke, at the iconic Place de la Republique.
More than 180,000 union members took to the streets in nationwide protests in France on Thursday (December 05), according to authorities.
The demonstrations taking place in some 30 French cities are part of a massive public-sector strike involving railway workers, teachers and emergency-room medics among others.
Several unions such as the CGT called to strike and protest to force President Emmanuel Macron to abandon plans to overhaul France's pension system.
Macron wants to simplify France's unwieldy pension system, which comprises more than 40 different plans, many with different retirement ages and benefits.
Rail workers, mariners and Paris Opera House ballet dancers can retire up to a decade earlier than the average worker.