The main rally through the center of Paris brought out some 45,000 campaigners, police said, while organizers put the figure at 107,000.
The march coincided with the return of the 'yellow vest' movement, whose so-called ultimatum rally saw violence break out and one of France's richest neighborhoods torched.
Read more: France to introduce plastic packaging tax
The environmental rally, however, was a peaceful affair and saw French movie stars, families, activists and politicians turn out.
Gloomy warningsMany protesters sang songs and held hands, while others carried signs reading "There is no Planet B" and "Dinosaurs also thought they had time."
"We are here to demonstrate against the inaction on climate change ... and against the multi-billionaires in their ivory towers," 18-year-old drama student Pierre-Loup Meriaux told the Agence France-Presse news agency.
Dozens of other climate rallies took place across France on Saturday including Lyon, Marseille, and Nantes.
The protests followed the formal launch of legal action this week by Greenpeace, Oxfam and two French environmental groups against the French state over its response to global warming.
The groups launched a campaign called "The Affair of the Century" in December, and have since garnered more than 2 million signatures to an online climate petition.
Macron's commitment questionedMany environmental activists think French President Emmanuel Macron's government isn't ambitious enough in cutting carbon emissions despite scientific proof that current levels of greenhouse gases are unsustainable. Read more: Climate change: Governments don't act? We do!
His passionate call this week to speed up the global fight against climate change did little to placate them.
Macron sees himself as a guarantor of the 2015 Paris climate accordand has stood up firmly to skepticism from US President Donald Trump.
Many of those protesting on Saturday were young people, some of whom had already marched the previous day in a youth protest for climate change action.
On Friday, hundreds of thousands of people skipped school to take part in the global student climate demonstration inspired by 16-year-old Swedish campaigner Greta Thunberg.
mm/aw (AFP, AP)
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