The evacuation started in Nice airport, but reasons are unclear. AP wrote this on Twitter.
BREAKING: AP journalist at Nice airport: Evacuation in progress, reason unclear .— The Associated Press (@AP) July 15, 2016
According to unconfirmed information, there can be a bomb in the luggage room.
Bomb-disposal experts are heading to the airport.
Also, as media reports, the suspicious truck was found in the city, it is inspected for explosives.