Troops at Paris' Orly airport shot dead a man who tried to grab a soldier's weapon, triggering a major security alert that shut down the airport, leaving thousands stranded.
The incident comes as France remains on high alert following a series of jihadist attacks that have claimed over 230 lives since January 2015.
Prosecutors said they had opened an anti-terror investigation.
Flights were halted at Orly for several hours, with incoming flights diverted and thousands of passengers stranded at Paris' second-largest airport, but normal service resumed mid-afternoon.
France goes to the polls on 23 April in the first round of a two-stage presidential election in which security is one of the main issues on voters' minds.
Interior Minister Bruno Le Roux said the man who was killed was "known to the police and intelligence services".
He said the suspect was also linked to an attack on police just north of Paris earlier on Saturday in which an officer was slightly wounded.
At the airport, the 39-year-old man knocked the soldier to the ground and grabbed at her rifle, a senior military source said.
The two other soldiers with her then opened fire, killing him, the source said.
No-one else was injured in the incident.
The incident took place at around 8:30am local time in the Orly-Sud terminal.
Around 3,000 people were evacuated from the building.
Addressing reporters at the airport, Mr Le Roux said the man had tried "but not succeeded" in his bid to grab the soldier's rifle who was on patrol with two colleagues.
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He said the same man was also suspected of opening fire on police during a routine traffic inspection in the northern Paris suburb of Garges-les-Gonesse at around 7:00am.
One officer suffered minor head injuries.
He was thought to have stolen a car and driven to Orly, Mr Le Roux said.
Sources close to the investigation said the man had committed several armed robberies and was investigated for radicalisation in 2015, although he did not feature on the list of those thought to pose a high risk.
Air traffic to Orly was suspended and all incoming flights rerouted to Paris' main Charles de Gaulle airport, north of the city.
Several planes that were preparing for takeoff or had just landed were held on the runway as the security operation unfolded.
Passengers in the Orly-Ouest terminal were kept inside the building, which reopened at around 12:00 Irish time.
Operations resumed soon afterwards at the southern terminal, where the incident occurred.
Elite police teams secured the airport and searched it for explosives but none were found.
'France still a target'
The shooting took place on the second day of an official visit to Paris by Britain's Prince William and his wife Kate, which was unaffected.
France remains in a state of emergency after a series of terror attacks, including the November 2015 massacre in Paris and a truck attack in Nice last July.
In mid-February, a machete-wielding Egyptian man attacked a soldier outside Paris's Louvre museum before being shot and wounded.
The soldiers on patrol at Orly airport belong to Operation Sentinelle, a force of 7,000 troops deployed in the capital and other cities after the January 2015 attacks in Paris.
On Thursday, a letter bomb exploded at the Paris offices of the International Monetary Fund, injuring a secretary who suffered burns to her hands and face.
French President Francois Hollande called that incident an "attack", saying it showed the country was "still targeted".