French refinery workers refused to back down on Thursday after the government moved to break a crippling fuel strike.
Ministers announced they were requisitioning workers to unblock a fuel depot after more than two weeks of strikes.
The move came as President Emmanuel Macron assured motorists that things would be back to normal in the next week.
But France's biggest trade union CGT said it would challenge the government's action and called for a wider strike in solidarity with its workers.
The union is demanding a 10 per cent pay rise for workers to reflect high inflation and bulging profits in the energy sector.
“Let's negotiate. You won't calm down the situation by force,” CGT secretary general Philippe Martinez told French television.
TotalEnergies, one of the companies involved, said it was willing to offer its employees a one-off bonus and discuss higher salaries once the refineries were unblocked.
The dispute has led to long queues of motorists blocking streets in Paris and other major cities in search of fuel, and reports of some people filling up over the border in Belgium.
As of Tuesday evening, 31 per cent of petrol stations lacked at least one grade of fuel, while the figure was 44 per cent in the Paris region, AFP reported.
The government said more requisitions could follow, including at a fuel depot in Dunkirk, northern France, if there was no breakthrough in talks between unions and bosses.
“We can't allow the country to be blocked because a few people always want to take things further,” Mr Macron told France 2 television.
The stand-off comes at a time when Mr Macron is preparing to push through a contentious pension overhaul despite likely resistance from unions and left-wing parties.
Mr Macron's planned reform, a key element of his re-election campaign in April, would result in the pension age being raised to 64 or 65 for most people, up from 62 currently.