At least seven people were wounded after a car rammed into the crowd in the French city of Bordeaux, authorities announced on Saturday.
The French Bleu Radio reported that the incident took place on the Rue du Professor Darget on Friday.
During the last period, protestors have been opposed to the French government's proposal to raise the retirement age to 64 from 62.
People stormed the headquarters of LVMH Thursday where the world's richest man, LVMH CEO Bernard Arnault, has offices.
French President Emmanuel Macron recommended increasing France's retirement age to 64 from 62 by 2030, indicating that France's pension system needs reform to be able to support future generations of retirees.
Last March, Macron invoked a constitutional power to force the bill through without a parliamentary vote.
"Apparently our government is struggling to finance our social security and pension system, so money needs to be found where it is, which is in billions in companies like LVMH," Fabien Villedieu, a union leader for Sud-Rail, told the French news channel BFM TV.