Troops are in control of Kidal airport in northern Mali, seizing a key position in one of three provincial capitals the Islamist militants took last year.
French and Malian troops have recaptured two of the other cities, Timbuktu and Gao, in recent days.
Colonel Thierry Burkhard of the French army said the airport was taken overnight and described the operation in Kidal as "ongoing".
Haminy Maiga, interim president of the Kidal regional assembly, said French forces met no resistance when they entered the town yesterday .
He said French troops and helicopters are in the city today.
The loss of Kidal would mean the Islamists no longer control any of the northern provincial capitals that they seized last April.