The bomb was found earlier this month by workers on a building site near Porte de la Chapelle, north of Gare du Nord.
The cross-Channel train operator has warned of “major disruption both to our services and transport throughout Paris on Sunday 17 February”.
Besides the main line north from Paris Gare du Nord to Lille and Calais, RER suburban rail and Metro services face disruption – as will the A1 autoroute.
Eurostar is telling passengers: “As a result of this operation we have had to substantially revise our plan for Sunday and will be running a modified timetable.
“This includes the cancellation of five services and the rerouting of one service to Marne-la-Vallée.
“Due to the high volume of customers and limited availability, we are advising that customers travelling this weekend change their plans.”
The train operator is offering free exchanges or full refunds.
Trains from Paris to London are worst affected. The four cancelled trains would normally carry up to 3,600 passengers.
Many passengers in the French capital for a late Valentine getaway could be stranded until Monday.
A single London-Paris service has been cancelled. Passengers on the southbound train diverted to Marne-la-Vallée, the station for Disneyland Paris, will be given tickets for the RER to the city centre.
The train operator said: “We’re very sorry for the inconvenience caused by a delay or cancellation to your Eurostar journey. We understand how stressful this can be and we will always try our best to prevent this.”
The deactivation will also cause problems for travellers between Paris Charles de Gaulle airport and the city centre.
The RER line to and from the airport is being closed between Gare du Nord and the station at Aulnay-sous-Bois from 9am to 3pm.
Porte de la Chapelle Métro station is closed, and bus and tram services will be disrupted.
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