
The unexploded bomb was found overnight by workers doing earthmoving activity near the tracks in the Seine-Saint-Denis area north of Paris, according to French Transport Minister Philippe Tabarot.
Bomb disposal experts were called to the scene, locals were evacuated and "a quite large" security perimeter was set up around the operation, he added.
Eurostar, operator of high-speed trains through the Channel Tunnel that links England with the European continent, announced the cancelation of all its services to and from its Paris hub at Gare du Nord and the U.K. and Belgian capitals.
"An unexploded bomb from the Second World War was discovered in this area," French national rail operator SNCF wrote on X. "Traffic will not resume until mid-afternoon, after formal authorization from the authorities."
Paris police also announced the closure of the A1 highway and sections of the capital's always-busy ring road around the city.
At Paris' usually bustling Gare du Nord station, bright red signs warning of disruptions greeted commuters.
SNCF says the station hosts 700,000 travelers per day, making it the busiest rail hub in Europe.

"Due to an object on the tracks near Paris Gare du Nord, we are expecting disruption to our services this morning. Please change your journey for a different date of travel," Eurostar wrote on X.
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