A youth throws an item on police forces during a demonstration in Paris on Thursday. AP

While the number of protesters has diminished, unions are keen to maintain almost three months of pressure ahead of a key court ruling next week on the retirement overhaul.

Two women hold up placards that read, 'The protest does not run out of steam, it suffocates under the tear gas' (L) and ' No Macron it is not good for us.' AFP

The controversial reforms seek to raise the retirement age from 62 to 64, while requiring people to work longer for a full pay-out.

Macron, currently visiting China, is facing the biggest challenge of his second term over the changes, defiantly refusing to budge despite sliding personal popularity ratings.

Demonstrations were held across the country, with people brandishing placards or waving union flags from Paris to the southern cities of Montpellier and Marseille.

"We haven't given up yet and we don't intend to," said 50-year-old public servant Davy Chretien, as he marched in Marseille.

A police officer uses his shield to avoid a stone thrown by youths during a demonstration in Paris. AP

The interior ministry said 570,000 people had demonstrated Thursday, sharply down from the 740,000 it counted last week.

Official figures remain well below organisers' counts, with the CGT union claiming 400,000 people had turned up to the Paris protest while the ministry tallied 93,000.

Restaurant set ablaze 

Among the crowd, some hardline protesters pelted paint against the shields of heavily equipped policemen outside La Rotonde, a famous Paris brasserie favoured by Macron.

A worker uses a fire-extinguisher to put out flames on the restaurant's awning during clashes with protesters in Paris. AFP

An AFP journalist saw a group of men dressed in black set off fireworks and throw stones toward the eatery.

The fire was caused by a flare thrown onto the fabric awning, and firefighters came to extinguish it. Macron held a victory party at the restaurant during his successful 2017 election bid.

Elsewhere in Paris, protesters attacked a bank branch, breaking glass and carrying off files and computer keyboards, an AFP correspondent saw.

Some threw projectiles at police, who responded with tear gas. The Paris police headquarters said there had been injuries among officers, without saying how many.

Striking railway workers also briefly stormed the former headquarters of the Credit Lyonnais bank, a building that now houses companies such as the BlackRock investment firm.

Riot police officers walk by burning bicycles during a demonstration in Paris. AP

In the western city of Nantes, protesters threw rocks at police, who also used tear gas, an AFP photographer saw. Protesters in the eastern city of Nancy meanwhile set fire to the front entrance of the local branch of France's central bank.

Interior Minister Gerald Darmanin said on Twitter that 111 people were arrested nationwide and 154 police wounded, some of them seriously.

Agence France-Presse