Coup leaders have made French influence one of their top targets as they rally domestic support
Niger's military rulers have announced that they have "instructed the police" to "expel" the French ambassador in Niamey, in a letter to Paris seen by the AFP news agency on Thursday.
According to the letter from the Ministry of Foreign Affairs, Ambassador Sylvain Itté "no longer enjoys the privileges and immunities attached to his status as a member of the diplomatic staff of the French Embassy".
His "diplomatic cards and visas" and those of his family members "are cancelled", the letter states, adding that the Niger police "have been instructed to proceed with the expulsion" of Mr Itté.
On Friday evening, the ruling military gave the French diplomat 48 hours to leave the country.
Paris refused, arguing that the new junta is illegitimate and thus has no authority to make such a request.
When this deadline expired, Mr Itté, whose work Emmanuel Macron praised on Tuesday, was still posted in Niamey.
On Thursday, the spokesman for the French general staff, Colonel Pierre Gaudillière, warned that "French military forces are ready to respond to any resurgence of tension that would undermine French military and diplomatic bases in Niger" and that "measures have been taken to protect these bases".
The Nigerien coup, which began this summer, has seen protesters gather in large crowds outside the French embassy, some waving Russian flags.
The junta, which styles itself the National Council for the Safeguard of the Homeland (CNSP), has made France, Niger's former coloniser, a top target of its efforts to establish full political control of the country.
CNSP member Colonel Obro Amadou recently told a supportive crowd gathered in a stadium that "The fight will not stop until the day there are no longer any French soldiers in Niger.
"It's you who are going to drive them out."
Another former French colony, Gabon, is also in the throes of a military coup that began when president Ali Bongo ostensibly won re-election in a disputed vote.
While Emmanuel Macron said earlier this year that the era of French interference in Africa is "over", many in Gabon, Niger and other ex-colonies remain resentful of France's military presence, its financial interests in extractive industries, and the sway it still holds in regional currency policy.