The French bomb squad was called in on Wednesday after a British tourist tried to take a ferry home from France with World War 2 bombshells in his suitcase.
The French police found three bombshells, understood to be from World War 2, inside his suitcase.
The potential risks attached ton the war relics were enough for police to evacuate the ferry terminal and to call in the bomb squad.
A large cordon was set up around the port, and an incoming ferry from the UK was diverted, reported French media.
Outgoing ferries were delayed by several hours, while local police took to Twitter to warn of the evacuation.
The British national who tried to take the shells is said to be around 40 years old.
He was promptly arrested by police, and is understood to have told them that he was a collector, although this remains unconfirmed.
The France 3 channel reported that the shells were from the D-Day landing beaches in nearby Normandy, although it remains unclear how they came to be in the man’s possession.
Officers are now trying to determine the origin of the shells, police spokesperson Sylvain Briand told the channel.
It is also uncertain whether the shells posed a tangible threat, although there were no reports of explosions and no one was reported to have been injured.
The incident marks the second time in recent memory that tourists have tried to take World War II souvenirs out of France and into the UK.
In 2013, a Eurostar passenger attempted to smuggle a military shell onto a UK-bound train by hiding it in his suitcase.
Much of the Gare du Nord station in Paris was evacuated at the time, although officials said there was no risk to the public.