The growing unrest, combined with rubbish piling up on the streets of Paris after refused workers joined in the action, has left President Emmanuel Macron with the gravest challenge to his authority since the so-called "Gilets Jaunes" (Yellow Vests) protests of December 2018.
Some 37% of operational staff at TotalEnergies' refineries and depots - at sites including Feyzin in southeast France and Normandy in the north - were on strike on Saturday, a company spokesperson said.
Meanwhile rolling strikes continued on the railways.
Riot police clashed with protesters on Friday evening in Paris as a demonstration took place at the capital's Place de la Concorde, near the Assemblee Nationale parliament building, resulting in 61 arrests.
"There is no place for violence. One must respect parliamentary democracy," Digital Transition and Telecommunications Minister Jean-Noel Barrot told Sud radio.
A further rally was planned in Paris later on Saturday while BFM television showed images of demonstrations already taking place in cities such as Compiegne in the north, Nantes in the west and Saint-Etienne in central France.
A broad alliance of France's main unions has said it would continue to mobilise to try to force a U-turn on the changes. A day of nationwide industrial action is scheduled for Thursday.
While eight days of nationwide protests since mid-January, and many local industrial actions, had so far been largely peaceful, the unrest over the last three days is reminiscent of the Yellow Vest protests which erupted in late 2018 over high fuel prices, and which forced Macron into a partial U-turn on a carbon tax.
Macron's overhaul raises the pension age by two years to 64, which the government says is essential to ensure the system does not go bust.
(Reporting by Dominique Vidalon; Editing by David Holmes)
By Dominique Vidalon