PARIS -- Thousands of demonstrators took to the streets of Paris and other French cities on Sunday to call for more ambitious measures in the fight against climate change.

The nationwide protests come after the lower house of parliament this week approved a climate bill aimed at curbing greenhouse gas emissions that environment activists say doesn't go far or fast enough.

"As it stands, the (proposed) law is a climatic and social failure," said a group of climate campaigners, "Ensemble pour le climat" ("Together for climate").

Greenpeace France denounced "the government's refusal to take action for climate."

Activists blame President Emmanuel Macron, who has been very vocal about his support for climate change action, for having "weakened" a set of measures initially proposed by a panel of 150 citizens who had worked for months on the issue.

The bill, which will now be debated in the Senate, includes a ban on domestic flights under two and half hours that can be done by train and measures to support renovation of high energy-consuming buildings and encourage greener cars.

Meanwhile, French newspaper Journal du Dimanche reported Sunday that a referendum to include the need to preserve the environment into the French Constitution, promised by Macron, won't be able to take place.

The change requires a parliamentary vote. The National Assembly, where Macron has a majority, largely approved it in March. But no deal has been found in the Senate, where the conservative party holds a majority.

Macron, speaking on the margins of a European Union event in the French city of Strasbourg, said the referendum bill "won't be abandoned."

"The text will continue living its parliamentary life, which is the only way to get a referendum on condition senators and deputies agree," he said, stressing the process is still several steps away from a definite vote in parliament.

Macron's office said that "the environment issue remains one of the priorities of the president."

About a third of France's 100 billion-euro (US$122 billion) rescue plan to help the economy recover from the coronavirus pandemic by next year will go to reducing emissions and protecting biodiversity.

Macron also pushed for beefing up the EU's 2030 targets to reduce greenhouse gases by at least 55 per cent compared with 1990 levels -- up from the previous 40 per cent target. Last month, the EU has reached a tentative climate deal to put the 27-nation bloc on a path to being "climate neutral" by 2050.