Cancelled trains, packed roads, frazzled nerves: Travellers across France scrambled on Friday to begin Christmas vacations upended by a weeks-long transport strike over a pensions overhaul that unions have vowed to defeat.

Hopes of a holiday truce were dashed after talks between the government and union leaders this week failed to ease the standoff, with train operator SNCF warning of massive cancellations ahead of the holidays.

Many stranded travellers turned to car rental agencies or sharing platforms, but the last-minute surge in demand meant vehicles were hard to come by.

"We've seen twice as many requests in some regions," mainly Paris and southwest France, said Robert Ostermann, France director for Europcar.

Trying to catch one of the few trains running
Trying to catch one of the few trains running AFP / Martin Bureau

Taxi companies in Paris had already stopped taking Friday reservations early this week as many metro lines remained shut, while Twitter has been awash with comments from irate Uber users asked to pay two to three times normal rates.

Others booked trips on buses, whose drivers have been allowed until December 24 to stay behind the wheel for more hours per shift to cope with an "emergency situation," according to a government decree published Wednesday.

Prime Minister Edouard Philippe said Thursday that talks had made progress and called on unions to lift the strike "so that millions of French can join their families for the end of this year".

Although the moderate UNSA union agreed, the hardline CGT and Force Ouvrier unions said they would not let up.

Paris braces for Christmas holiday travel chaos amid pensions strike
Paris braces for Christmas holiday travel chaos amid pensions strike AFPTV / Fabien NOVIAL

"It's time for the government to realise that this project is a serious mistake," FO chief Yves Veyrier told France 2 television on Friday.

"The only concrete thing is that the prime minister did not hear what the street is saying," Philippe Martinez, leader of the CGT union, said after talks with the government.

How older people in the EU are faring
How older people in the EU are faring AFP / Thomas SAINT-CRICQ

Late Friday, the railway workers branch of the more moderate CFDT union also opted to continue the labour action.

President Emmanuel Macron wants to forge the country's 42 separate pension regimes into a single points-based system which the government says will be fairer and more transparent.

It would do away with legacy schemes that offer early retirement and other advantages to mainly public-sector workers, not least train drivers who can retire as early as 52.

But while some unions support a single system, almost all reject a new "pivot age" of 64 -- beyond the legal retirement age of 62 -- which workers would have to reach to get a full pension.

They are hoping for a repeat of 1995, when the government backed down on pension reform after three weeks of metro and rail stoppages just before Christmas.

An Ifop poll released Thursday found six out of 10 respondents oppose the "pivot age" and more than half have sympathy for the strike despite the daily transport misery for millions.

The protest is taking a heavy toll on businesses, especially retail during one of the busiest periods of the year, with industry associations reporting turnover declines of 30 to 60 percent from a year earlier.

Junior Economy Minister Agnes Pannier-Runacher has urged people to patronise local businesses during the crucial holiday season, saying "it's time to give them a hand."

On Friday, the Chamber of Commerce and Industry of Paris, which represents business interests, urged the government to take "more vigorous measures" to help traders deal with the strike's impact, saying many risked going under.

This weekend, the last for Christmas shopping, the RATP and SNCF operators said public transport in Paris and connections with the capital's outlying suburbs will again be heavily slashed, and only half of high-speed TGV intercity trains will be running.

"Trains on slow down, negotiations too... tough times in the stations to get away for Christmas break," a Liberation newspaper headline said.