Protesters again poured into streets across France on Friday hoping to derail a hotly contested pension overhaul, whose fate will soon be in the hands of lawmakers after weeks of crippling transport strikes.

Union leaders insist they have widespread public support for what has become their biggest show of strength in decades, against a reform they say will force millions of people to work longer before retiring.

They admit it is a make-or-break moment for the protests launched on December 5, which have seen train and metro drivers as well as teachers, hospital workers and others walk off the job.

On Friday, the government unveiled its final version of the draft law, which is expected to easily clear parliament where President Emmanuel Macron's centrist party holds a majority.

"This government is arrogant, it's not taking into account what we're saying, it's no longer listening to unions," said Cecile Chamignon, 40, a civil servant protesting in Lyon.

Some 80,000 people marched in dozens of cities across France, according to police estimates, not including the tens of thousands who demonstrated in the capital Paris , gathering a stone's throw from the presidential palace.

- Eiffel Tower closed -

It was the seventh day of mass rallies since the crippling transport strike was launched last month by unions hoping to force Macron to back down on his push for a "universal" pension system.

The start of the week brought relief for commuters as many metro drivers returned to work, leaving unions to resort to other forms of protest, such as power cuts and port blockades.

French unions are seeking to pressure Macron into backing down on his push for a 'universal' pensions system / © AFP

But public transport in the capital was again severely disrupted on Friday.

The Eiffel Tower was also shut for the day as some workers at the iconic landmark joined the protests.

Macron's reforms would sweep away 42 separate pension schemes, some dating back hundreds of years, that offer early retirement and other benefits to public-sector workers as well as lawyers, physiotherapists and even Paris Opera employees.

Critics say the new points-based system will force millions of people to work longer.

They also say the plan will force people to invest in private US-style pension plans, accusing Macron, a former investment banker, of rolling out a red carpet to foreign asset managers like BlackRock -- claims the government has denied.

- 'Explosive' -

Police were again deployed en masse in Paris and elsewhere on Friday to avoid the kind of rioting and vandalism seen during many anti-government protests over the past year.

A protester wearing a gilet of the moderate CGT union brandishes a smoke bomb during Friday's demonstration in Lyon, southeast France / © AFP

Law enforcement has also been accused of heavy-handed tactics, after a series of videos showed officers beating demonstrators or firing rubber bullets at close range.

Despite a series of concessions to groups including police, pilots and many transport workers, the government has largely held firm on a reform promised by Macron during his 2017 presidential campaign.

He says the new system will be more transparent and fairer, in particular to women and low-income workers such as farmers.

But even France's moderate CFDT union, the country's largest and a backer of Macron's reform, has warned that the standoff might worsen unless the government definitely drops its plans to defer the age for a full pension from 62 to 64.

"If there's no progress, the situation is going to remain highly explosive," CFDT chief Laurent Berger said Friday.

On Friday, the FO and the CGT, the powerhouse unions in the public sector, called for a new day of walkouts for January 29.