PARIS - Tens of thousands of people marched in Paris on Sunday to protest rising living costs, amid an increasingly tense political atmosphere marked by strikes at oil refineries and nuclear plants that threaten to spread further.

The march had been planned long before the strikes by a coalition of left-wing parties eager to capitalise on the cost-of-living crisis and assert itself as the leading opposition force to President Emmanuel Macron.

But on Sunday, organisers signalled that they intended to build momentum from the climate of social unrest to increase pressure on Macron's government.

"We need to be tougher," said David Guiraud, a lawmaker from France Unbowed, the hard-left party that led Sunday's protest.

He added that the government could "no longer decide on its own."

Macron finds himself in a perilous situation. He is simultaneously facing discontent over shortages at gas stations, along with labour strikes and a fierce opposition in the National Assembly, the lower and more powerful house of parliament, which may try to bring down his government this week over a disputed budget Bill.

"We are entering a particular and quite extraordinary cycle," said Jean-Luc Melenchon, leader of France Unbowed, as he led the protest on Sunday.

At the heart of the matter are rising living costs. Already a key topic in this spring's French presidential campaign, it has now moved to the top of French people's concerns, according to a recent study, far ahead of more traditional issues like climate change, security or immigration.

Although lower than in the rest of Europe, inflation in France has surpassed 6 per cent, jacking up the prices of staples like meat and pasta.

Parliament passed an inflation relief package this summer, but it has not completely offset soaring energy costs, which are rising because of Russia's war in Ukraine.

The situation has been compounded by strikes at many refineries, which have left nearly a third of all gas pumps across the country fully or partly dry and have forced drivers to line up for hours at stations.

Workers have been picketing for higher wages in line with inflation, as well as a greater share of the surging profits of energy giants.

But their demands have resonated far beyond refineries, prompting nuclear plants and railroad workers to stop work as well or plan to. NYTIMES