Police in Paris partly evacuated Europe's busiest train station, the Gare du Nord, on Friday after an inactive explosive shell was discovered in a passenger's bag, sources said.

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.