PARIS — French Prime Minister Sébastien Lecornu resigned after less than a month in office on Monday and less than 24 hours after naming a new government that prompted a key coalition ally to withdraw support.

The move deepened the country’s political crisis and left President Emmanuel Macron with few options.

The presidency said that Macron, who has been hitting record lows in opinion polls, accepted the resignation.

Lecornu had replaced his predecessor, François Bayrou, on Sept. 9 to become France’s fourth prime minister in barely a year during a prolonged period of political instability. Lecornu is now the shortest-serving prime minister in the history of the Fifth Republic, which started in 1958.

French politics have been in disarray since Macron called an early legislative elect

See Full Page