A man has been shot dead at Paris Orly airport after taking a soldier's gun and fleeing into a shop.
Unconfirmed reports claim a second man has also been shot dead.
Anti-terror police are searching the airport for possible accomplices and explosives, and authorities have warned the public to stay away.
Passengers recounted shots being fired within the south terminal at 8.30am today.
Video taken from the airport - the second largest serving the French capital - show panic scenes as people were evacuated.
Passengers landing at Orly have been kept on planes while the anti-terror operation is carried out.
French TV network BFMTV reports that a man attempted to grab the weapon of a solider in the airport’s southern terminal. The solider opened fire, killing the attacker.
The airport has been evacuated and police are searching for possible accomplices. A search is on to determine if any explosives were left.
French national police tweeted: 'Ongoing police operation, we recommend that you avoid the airport.'
One passenger wrote on Twitter: 'SHOTS FIRED AT THE ORLY AIRPORT SOUTH TERMINAL!'
And passenger Isabelle Raynaud said she was not being allowed to leave her plane as a result of the operation.
She wrote: 'Stuck in the plane to #orly we are prevented from disembarking. There have been shots...'
The airport - the second largest serving the French capital - was evacuated, as anti-terrorist police flooded into the area.
A police source said the suspect had been killed by troops taking part in Operation Sentinelle, a security initiative that has been in place since 2015, and involves some 7000 soldiers.
'It happened in the south terminal - it is being evacuated,' said a source at the airport. 'Passengers and staff are being moved out of the areas.'
France is currently under a state of emergency following a series of attacks by Islamic State and al-Qaeda operatives over the past two years.
Today's incident comes as the Duke and Duchess of Cambridge visit Paris. They are currently staying at the British Ambassador's residence by the British Embassy.
The Royal couple will attend the Invalides military monument later today to meet victims of terrorism.
Then they will attend this afternoon's rugby international between France and Wales.
