Striking employees at the Esso-ExxonMobil refinery in Normandy have unanimously voted to renew industrial action.
It follows the government's announcement that it will use its emergency powers to force essential workers back to work at Gravenchon-Port-Jerome refinery in northwest France following the government's requisition threats on Tuesday.
"Faced with the continuation of the strike by some of the personnel at Port-Jerome in Normandy, the government is launching the requisitioning of essential workers at the depot," an official at the energy ministry said.
Pay-related industrial action has brought work to a standstill at six of the country's seven fuel refineries, leading to petrol and diesal shortages, exacerbated by panic-buying from drivers.
But the CGT union representatives say they will go to court to get the requisition cancelled.
"You have to know that we are going to fight against this because it clearly challenges the right to strike. We are saying, unfortunately, we are no longer in a state of law and freedom," said Christophe Aubert, a hard-left CGT union coordinator for the Exxon Mobil group.
"Our right to strike is under frontal attack, but we are not going to let it happen," he added.
Workers who refuse to return to work could face fines or jail time.
"No one has received a requisition. We are on strike, we are in the framework of the protocol, that is to say we are going back to finish stopping the units, but no requisition at the moment," said Gil Villard, the CGT union secretary at Esso-Fos.
Two of the striking refineries are owned by Esso Exxon-Mobil, while its rival TotalEnergies owns the other four.
According to the CGT union, strikers at Totalenergies have renewed their calls for a 10% pay rise in line with inflation and soaring energy bills.
It called requisitioning the "choice of violence", adding that it would lead the union to suspend "its participation in meetings with the government and business leaders during this period".
Until now, the government had been reluctant to inflame the conflict but was also aware of growing frustration and economic damage caused by drivers spending hours queuing at filling stations.
Left-leaning political parties have vowed to march on Sunday against the cost of living crisis.
I hope this is the spark that begins a general strike," said leading Greens party MP, Sandrine Rousseau.
President Emmanuel Macron is looking to push through a highly contentious pension reform by the end of the winter despite warnings from some allies about the risk of strikes and demonstrations.
Labour unions and left-wing political parties have vowed to try to block the reform, which would see the pension age raised from 62 to 64 or 65.
The fuel shortages have particularly affected motorists in Paris.
Some departments have also introduced pump rationing to a maximum of €30 of fuel per tank.