Like recent coups in neighboring Burkina Faso and Mali, the military takeover in Niger came amid a growing wave of anti-French sentiment, with some locals accusing the European country of interfering in their affairs.
In a statement, the junta-appointed foreign ministry said the decision to expel the ambassador was a response to actions taken by the French government that were "contrary to the interests of Niger."
It said these included the envoy's refusal to respond to an invitation to meet Niger's new foreign minister.
The French foreign ministry did not immediately reply to a request for comment.
Official-seeming statements were shared widely online on Friday that appeared to show Niger ordering the U.S. ambassador and German ambassador to leave the country in similar terms to the statement about the French envoy.
FILE — French journalist Olivier Dubois, center, is greeted by Sylvain Itte, French Ambassador to Niger at the VIP lounge at the airport in Niamey, Niger, Monday March 20, 2023.
The U.S. State Department on Friday said Niger had informed it this had not been issued by its foreign ministry. "No such request has been made to the U.S. government," it said.
A source in the junta and a Nigerien security source said only the French ambassador had been asked to leave.
The coup has pushed Niger's long-standing relationship with France to breaking-point and this latest move raises further doubts about the future of joint military efforts to fight an Islamist insurgency in the conflict-torn Sahel region.
France has called for President Mohamed Bazoum to be returned to office following his ouster and has said it would support efforts by West African regional bloc ECOWAS to overturn the coup.
It has also not officially recognized a decision by the junta in early August to revoke a raft of military agreements with France, saying these had been signed with Niger's "legitimate authorities."
The deterioration in Niger-France relations echoes post-coup developments in Mali and Burkina Faso, which have booted out French forces and severed long-standing ties.
Niger has strategic significance as one of the world's biggest producers of uranium and as a base for French, U.S. and other foreign troops that are helping to fight Islamist militant groups in the region.