France's military has been in action against Islamist militants in Mali since Friday, helping government forces recapture the central town of Konna.
A resident in Gao told AFP news agency all Islamist bases in the town had been destroyed and the militants had fled.
French Foreign Minister Laurent Fabius said the Islamist advance in Mali had been brought to a halt.
"Stopping the terrorists, that's done," he told RTL radio. Had France not intervened, there was a risk that the Islamists could have advanced as far as the capital, Bamako, he said.
Islamist groups and secular Tuareg rebels seized northern Mali in April 2012.
BBC News - France Rafale jets target Gao in eastern Mali