The pullout, ordered by Niger's military rulers, started last week after the July ouster of president Mohamed Bazoum, a key ally of Paris, had thrown France's strategy for the Sahel region into disarray.

The convoy "has arrived without any particular problems" in N'Djamena after 10 days on the road and in coordination with Nigerien forces, army spokesman Pierre Gaudilliere told AFP.

The troops will depart by air from Chad to France, with the pullout expected to be completed by the end of December.

Gaudilliere said France's forward bases in Ouallam and Ayorou in northwestern Niger, near the borders with Burkina Faso and Mali, had been partially vacated.

The "three borders" zone is known as a haven for the Islamic State group (IS), but the threat level for troops travelling from Niger's capital Niamey to N'Djamena was "low", a French military source told AFP.

France deployed 1,400 soldiers, fighter jets, drones, helicopters and armoured vehicles, in Niamey and western Niger to battle fighters linked to IS and Al-Qaeda.

N'Djamena is the site of France's military headquarters for the whole Sahel region, with around 1,000 troops there.

From Chad, French troops can leave by air with their most sensitive equipment. However, most will have to be moved by land and sea.

The French military spokesman said some heavy military equipment was expected to be moved by sea but the route had yet to be decided in talks with local governments.

"When we speak about an orderly retreat, security and cooperation, all these words are important," he said.

It is the third time in 18 months that French troops have been sent packing by a former African colony, dealing a severe blow to France's influence on the continent and prestige on the international stage.

France earlier pulled out troops from Mali and Burkina Faso, which have undergone coups in the past two years.

On Wednesday, French President Emmanuel Macron hosted Chad's President Mahamat Idriss Deby for talks at the Elysee Palace to discuss regional issues and the return of France's "military assets".