France's Transport Minister Philippe Tabarot announced on Friday afternoon that the danger was over and the bomb had been defused, and that traffic would resume from 5 pm. He added that the bomb contained 200 kilos of explosives.
We are happy and relieved that this is over, he said.
The old bomb was found "right on the tracks" during the night in connection with maintenance work in the suburb of Saint-Denis, according to the state-owned railway company SNCF.
Gare du Nord is located in the northern part of Paris and is the country's most heavily trafficked railway station with around 700,000 passengers per day.
In total, around 500 departures were cancelled due to the bomb.