Gare Du Nord in Paris has reopened after a security alert saw the station briefly closed.
The station, in the north of the city and home to Eurostar services, was evacuated and cordoned off by heavily armed police late on Monday.
No further details have been given about the operation.
Footage posted on social media showed many police vehicles guarding the perimeter of the station.
However, there are reports in French media that police were looking for three suspects.
France remains under a state of emergency following the Paris attacks of 2015, with security on high alert across the country.
The November 2015 attacks by so-called Islamic State killed 130 people.