The government intends to hike the retirement age to 64 from the current 62 and streamline the pension system under changes even some supporters view as risky and likely to provoke backlash.
The country's eight biggest unions immediately called a day of protests on January 19 which "kicks off a powerful movement for pensions for the long term", according to their joint statement.
It will be the first time in 12 years, since the last pension changes, that all of France's unions are united, with the head of the more moderate CFDT, Laurent Berger, calling the reform "one of the most brutal of the last 30 years."
Presenting the outlines of the government's plans after months of suspense, Prime Minister Elisabeth Borne said Tuesday that doing nothing about projected deficits for the retirement system would be "irresponsible".
"It would lead inevitably to a massive increase in taxes, a reduction in pensions and would pose a threat to our pensions system," she said.
Opinion polls show that around two thirds of French people oppose raising the retirement age and the move comes amid high inflation and with the country still recovering from the Covid-19 pandemic.
"By asking French people to work for longer, even though life expectancy with good health is 64, Emmanuel Macron is offering no prospect of a peaceful life that our fellow citizens deserve," far-right leader Marine Le Pen said afterwards.
'Anxiety and Fears'
Macron's last attempt at pension reform in 2019, aborted a year later when Covid-19 hit Europe, prompted the longest strike on the Paris transport network in three decades.
The 45-year-old centrist put the issue at the heart of his successful re-election campaign last year, pointing to forecasts that the system would fall into heavy deficit at the end of the decade.
As well as raising the retirement age, the changes would increase the contributions required of workers before they can claim a full pension, effectively extending the careers of millions.
It would also put an end to special pension privileges enjoyed by workers in some sectors, such as the Paris transport network, but only for new entrants.
Despite pledges to raise the minimum pension to nearly 1,200 euros ($1,290) a month, left-wing opponents say the reform is unfair because it will disproportionately affect unskilled workers who started their careers early, sometimes in their teens.
French economist and author Thomas Piketty wrote in Le Monde newspaper at the weekend that the projected savings of 20 billion euros a year by 2030 "will weigh down entirely on the poorest".
Some ruling party lawmakers have spoken privately of their concern about protests, while one of Macron's closest political allies, Francois Bayrou, has warned that the government has not explained itself sufficiently.
"I'm very aware that making changes to our retirement system is causing anxiety and fears among French people," Borne said.
Yellow Vests II?
As well as paralysing strikes, the government risks a repeat of spontaneous protests in 2018 when people wearing fluorescent yellow safety jackets began blockading roads, sparking what became known as the "Yellow Vest" revolt.
The often violent display of defiance struck fear into the heart of government, leading Macron to promise a gentler, less authoritarian style of governing.
Bruno Cautres from Sciences Po university in Paris told AFP that the national mood was one of "pessimism, fatalism and anger", but he did not expect another uprising.
The government appears to be banking on the country acquiescing to a change that is widely disliked but viewed as inevitable.
It received a boost on Thursday when the right-wing opposition Republicans party welcomed the proposals and signalled it would vote in favour of them, potentially clearing the way for quick approval in parliament next month.
The once-mighty French unions are also in steady decline and have repeatedly lost out in their struggles with Macron.
"If they lose this battle again, if they get nothing on the pension issue, it will be complicated for them to manage the aftermath," said Stephane Sirot, a historian and author specialising in the French labour movement.