Police in Paris evacuated the mainline railway station Gare du Nord on Monday night (May 8) cordoning off the area due to a security alert.
Media reports claimed they were searching for three men said to be “dangerous” who were believed to have arrived on a train from Valenciennes, a town in northern France close to the Belgian border.
French intelligence allegedly received information on Friday that the men were due in the country and could be seeking to carry out an attack.
Unconfirmed reports said two of the men were thought to be Belgian nationals and one Afghan.
After two hours police reopened the station releasing no details about the operation.
France is under a state of emergency after a string of terror attacks in the last two years left more than 230 dead. The latest occurred on April 20 when an Islamist radical shot dead a policeman on the Champs-Elysées in Paris before being gunned down by other officers.
Security has been particularly tight in the final stages of France’s presidential elections, which ended on Sunday with the election of centrist Emmanuel Macron.