France's largest union, the CGT, has opted for a do-or-die strategy of choking off the nation's fuel supplies after failing to galvanise the masses against the Socialist government's labour reforms, analysts say.
Given what is at stake for both parties, one politician described the battle as a "fight to the death".
A springtime of discontent over the job market reforms, seen as heavily weighted in favour of employers, has run out of steam after wresting a handful of concessions from the government.
France has a reputation for chronic strikes and protests, but union action does not often force a major government climbdown.
Undeterred, the CGT last week launched blockades of oil refineries and depots, threatening to paralyse the country unless the labour reforms are scrapped altogether, barely two weeks before France begins hosting the Euro 2016 football championships.
The union is "going for broke" with headline-grabbing actions because it is "having trouble inspiring the masses," said political scientist Dominique Andolfatto.
CGT leader Philippe Martinez (see below) himself posed for the cameras last weekend as he threw a tyre onto a flaming barricade set up at a fuel depot in northern France.
The union, formed in 1895, has been dominated by Communist Party stalwarts since World War II, but Martinez is its first leader who is not a card-carrying communist -- he left the party in 2002 while retaining "a certain number of ideals".
Since the 1990s, the CGT has been increasingly open to compromise, but Martinez is now returning the union to its roots, said labour rights specialist Bernard Gauriau.
"He is adopting a more trenchant attitude than his predecessors, often stressing the theme of class struggle, to rally the ranks," Gauriau said, adding that the move is a way of "distinguishing himself from other unions".
Protests over the proposed labour reforms reached a fever pitch at the end of March, when some 390,000 people took to the streets across France, according to an official count, while organisers put the number at 1.2 million.
That coincided with the birth of a new youth-led movement called "Nuit Debout" (Up All Night), which has seen advocates of a broad spectrum of causes gather in city squares at night to demand change.
But both movements have largely fizzled out, even though nearly every week has seen strikes and protests, some descending into violence.
In the general public, while seven in 10 people still oppose the labour reforms, 58 percent want the protests to stop, according to a recent poll.
The CGT counts only 700,000 members out of an overall workforce of 24 million, but insists the government is to blame for the current showdown because it has not responded to workers' demands.
Martinez, 55, was re-elected in April at a time of deep disappointment within a union that had endorsed Francois Hollande for president in 2012.
"Was gutting the labour code in Hollande's programme?" Martinez asked. "The government has turned its back on its commitments and it is paying the consequences."
If the CGT's current gambit fails, it will be the second time since 2010, when right-wing president Nicolas Sarkozy pushed through the pension reform despite weeks of street protests and strikes.
Although less than 10 percent of the French workforce is unionised today compared with some 30 percent in 1950, the unions enjoy key bargaining power within companies, which helps them influence government policy.
But the last time a mass protest movement forced a truly memorable government climbdown was in 1995, when then-president Jacques Chirac made a first stab at the pension reform that Sarkozy achieved.
Unemployment still high
Parisians in particular remember that cold December when public transport was shut down completely -- wiping out crickets living in the city's metro system normally warmed by the passing trains.
Hollande's labour reform package was initially billed as a signature initiative to address the issue he has staked his presidency on -- unemployment -- which remains at a stubborn 10 percent with elections less than a year away.
Pressure from the street, as well as parliament's back benches, caused the government to water down the proposals, which only angered bosses while failing to assuage critics.
But the CGT has made a stark choice, said labour historian Stephane Sirot.
"Once the CGT adopted a strategy demanding the withdrawal (of the reforms) it has only two options: either it stops the movement or it gives it a new impetus."