Between 200 and 300 demonstrators, waving flags and carrying flares, occupied Euronext, chanting: "We are here, we are here, even if Macron does not want it we are here".

It's a slogan which has become popular as huge crowds have gathered in sometimes violent protests and strikes that erupted in January.

They also called on Mr Macron to resign, another familiar demand.

The lobby of the firm, located in La Defense, Paris' business district, was filled with red smoke from demonstrators' flares.

It is not clear how long the protesters stayed in the offices.

Elsewhere in the French capital, wooden pallets were set alight as striking rail workers held a peaceful demonstration at the Gare de Lyon railway station, as part of what was billed as a "day of expression of railway anger".

Protesters in the northern city of Lille walked along the railway line, blocking all train traffic for about one hour before leaving peacefully.

Several unions joined a strike at the national railway company SNCF, slightly disrupting train traffic on Thursday.

Some regional lines and Paris suburban trains were affected, while high-speed trains were running almost as normal, the SNCF said.

Mr Macron signed a bill raising the state pension age from 62 to 64 at the weekend, a widely unpopular move in a country that cherishes its retirement years.

Fabien Villedieu, a unionist with rail operator, Sud-Rail, said: "We are told that there is no money to finance pensions."

[But there is] "no need to get the money from the pockets of workers, there is some in the pockets of billionaires," he said.

Earlier this month, similar scenes occurred at Blackrock's Paris offices.

The president himself was heckled as he visited a school in the southern French town of Ganges, his second public outing since signing the bill into law.

Protesters held a few hundred metres away by police also chanted against the pension reform.

Opinion polls show a vast majority of voters oppose the pension reform, but Mr Macron shrugged off the protests.

He was pictured smiling and taking selfies as he told a group of students, parents and teachers "there is a bit of everything. There are people who are happy, and people who are not happy."