Europe's busiest railway station, the Gare du Nord, was partly evacuated on Friday after an inactive explosive shell was found in a passenger's bag.
As per the media reports, the police said that the shell was found as part of a random check at the station, which serves as a stop for the Eurostar from London, the Thalys from Belgium, Germany and the Netherlands, four suburban train lines, and two busy Paris metros.
A source close to the investigation said the man, who was arrested, was a soldier.
Arrivals and departures were temporarily disrupted before being resumed later Friday.