French police said they are searching for three men suspected of plotting an Islamic State-inspired attack, after authorities conducted a major operation at a Paris train station.
A ticket vendor in the northern town of Valenciennes thought he recognised one of the three men listed on police wanted notices, prompting the operation and temporary closure of Gare du Nord late on Monday.
No arrests have been made.
Rocco Contento, of Unite SGP police union, told The Associated Press the vendor informed local police.
The suspects have been identified as Belgian citizens Bilal Al Marchohi and Tarik Jadaoun, and Afghan national Zabihullah Sarwari.
The busy Gare du Nord - the terminus of a large suburban and national rail network as well as the hub for Eurostar trains from London - was evacuated after 11pm on Monday night as officers from the special BRI intervention force started pouring into the station.
A security perimeter was established and all passengers on the train from Valenciennes were taken to a nearby brasserie to be searched, Mr Contento said.
"Unfortunately it was determined that the person was not in the train," he added.
Police said the operation went smoothly and ended early on Tuesday.
The operation came the day after a tense presidential election won by independent Emmanuel Macron, who has said one of his top priorities will be ensuring France's security.
France remains under a state of emergency imposed after a series of Islamic extremist attacks in 2015.