Police officers shot and killed a man who brandished a knife at the Charles de Gaulle airport outside Paris on Wednesday, police and airport sources said.

"Officers neutralised a threatening individual in possession of a knife at the Roissy-Charles de Gaulle airport," the Paris police department said on its Twitter account.

An airport source said the incident occurred at the busy Terminal 2F at around 8:20 am (0620 GMT), when "a homeless man started bothering security agents and border police were called in to remove him".

Initially the man left while yelling curses but he soon returned and brought out a knife, when one of the officers fired his weapon.

An AFP photographer who witnessed the scene said "a large person of colour brandished something that looked like a knife at the police".

"He was ordered to stop but kept advancing toward them, and an officer fired a single shot."

The man was quickly put on a stretcher and evacuated, the photographer said.

Security forces have been on high alert for terrorist attacks since a wave of jihadist killings that have killed more than 250 people since 2015, often by so-called "lone wolves" who often target police.