At least 900 hectares (2,223 acres) of forest burned southeast of Carcassonne in the French department of Aude, France Bleu radio station reported on Thursday.
The fire began on Wednesday, according to the France Bleu radio station. It is now spreading toward the communes of Pradelles-en-Val and Montlaur 18 kilometers (11 miles) southeast of Carcassonne.
Over 500 firefighters and five aircraft have reportedly been mobilised to extinguish the fire.
The mayor of Pradelles-en-Val told the radio station that 22 people had been evacuated.