Tens of thousands of people marched in Paris and other cities across France on Wednesday to denounce the government’s pension plan as unfair to female workers, in demonstrations meant to coincide with International Women’s Day.

The show of anger against President Macron’s plan to raise the retirement age to 64 from 62 is set to continue in coming days and even weeks, as train and metro drivers, refinery workers, garbage collectors, and others have said they would continue ongoing strikes. Unions aim at maintaining pressure on the government as senators debate the changes.

Feminist activists say the pension reform would further deepen gender inequalities at work, where women’s wages are on average 15.8 percent below men’s.

For Mr. Macron, pension overhaul is a flagship project, and he is staking his reputation as a credible reformer on its success. Polls say about two-thirds of the French now oppose it — including 74 percent of women, according to a recent survey by the Elabe institute.

A hard-left lawmaker who took part in the Paris march,  Clémentine Autain, said there are two reasons for the protest: “first, because, like every year, on March 8, we march to demand equality and also, to ask for this pension reform bill that is going to make women poorer to be withdrawn.”

The bill would raise the minimum pension age and require 43 years of work to earn a full pension, amid other measures. The government argues that the current system is expected to dive into deficit within a decade as France’s population ages and life expectancy lengthens.

About 150 employees from the Louvre museum gathered Wednesday morning in the room where Leonardo da Vinci’s “Mona Lisa” is displayed, brandishing a huge banner reading, “No to working longer,” in front of the iconic painting, a union statement said. They wanted to show “solidarity towards the women’s fight for their rights across the world” and to denounce the pension plan’s impact on female workers, the statement said.

The Louvre museum said on its website that it is open to visitors but warned that some rooms are closed due to the protests.

The continuing strikes and protest action come after more than a million demonstrators marched in cities and towns across France on Tuesday, in what unions see as the biggest show of force against the planned changes since the beginning of the movement in January. Unions demand the withdrawal of the reform bill. The bill is under debate in the senate this week. 

“We are aware that the effort required from the French does not win the support from a majority,” a government spokesman, Olivier Véran, said Wednesday. “But we are convinced that alternatives — raising taxes, increasing the [state] debt, decreasing pensions — would not win more the support of public opinion.”

Opinion polls consistently suggest that most French voters oppose the pension plan. Mr. Véran hoped Article 7 of the bill, which is focusing on raising the retirement age to 64 from 62, would be adopted by the senate later on Wednesday. Talks at the upper house of parliament are scheduled to last until the end of the week.

Meanwhile, rail and metro authorities announced that trains, including international lines, and the Paris metro will be disrupted severely on Thursday, like on previous days. In addition, up to a third of all flights are expected to be canceled in French airports.

Oil shipments in the country were halted Wednesday for a second consecutive day amid strikes at the refineries of TotalEnergies and Esso ExxonMobil, according to the CGT union. Paris garbage collectors also decided to continue the strike. Unions have called for a new day of nationwide demonstrations on Saturday.

Mr. Macron has vowed to go ahead with the bill, which he presents as key to his pro-businesses economic policies. Left-wing lawmakers say companies and the wealthy should pitch in more to finance the pension system.

On Thursday, youth organizations representing students who haven’t even entered the workforce yet are seeking to mobilize young people to take to the streets to share concerns about retirement rights.

While the measure has a good chance of winning Senate approval, unions hope that strikes and protests force the government to make concessions as the bill continues its way through the often tangled French legislative process.