People (More than 100,000) protested across France on Saturday against the appointment of the center-right politician Michel Barnier as the new prime minister.
His appointment follows an inclusive election in which the left-wing bloc - the New Popular Front (NPF) - won the largest number of seats.
The protests were called by trade unions and members of the NPF, who are furious that their own candidate for prime minister was rejected by President Emmanuel Macron.
Mr Barnier, the EU's former Brexit negotiator, said he is open to forming a government with politicians across the political spectrum, including the left.
The interior ministry said 110,000 protested nationwide on Saturday, including 26,000 in Paris, though one protest leader claimed the figure was 300,000.
Jean-Luc Mélenchon, a veteran firebrand from the radical France Unbowed party, called for the "most powerful mobilization possible" in national marches.
Around 130 protests were scheduled, with the biggest setting out from central Paris on Saturday afternoon.
Mr. Mélenchon joined the Paris protest, giving a speech on the back of a float emblazoned with the slogan: “For democracy, stop Macron’s coup”.
The demonstrators are also using slogans such as "denial of democracy" and "stolen election".
Parties on the left are angry that their candidate for prime minister, Lucie Castets, was rejected by Mr Macron, who said she had no chance of surviving a vote of confidence in the National Assembly.
Mr Barnier may be able to survive a confidence vote because the far right, which also won a large number of seats, has said it won't automatically vote against him.
That has led to criticism that his government will be dependent on the far right.
"We have a prime minister completely dependent on National Rally," Ms Castets said.
Mr. Barnier spent Saturday afternoon visiting a children’s hospital in Paris, where he highlighted the importance of public services but told healthcare workers his government "is not going to perform miracles", local broadcaster BFMTV reported.
