A Reuters witness at the scene said there were between 20 to 30 police vans outside the station in central Paris with security forces wearing balaclavas and carrying assault weapons.
"End of security checks. Gradual return to normal," Paris police said in a tweet.
Authorities gave no other details about the nature of the operation.
Over the past two years, the country has been hit by a series of Islamist militant attacks in Paris and other cities in which more than 230 people have been killed.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)
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