For more than a week, French rescuers tried to pull a beluga whale out of the Seine, which swam into the river and was found 70 km from Paris. This is reported by the BBC service.
"We regret to announce the death of the whale," the French authorities quoted the portal as saying.
During transportation, the emaciated animal developed breathing problems and the animal had to be euthanized.
The whale was caught from the river with nets and placed on a barge, from where the animal was moved to a refrigerated truck.
After that, the rescuers intended to transport the whale to a specially prepared seawater lock in the city of Ouistreham.
According to French scientists, the nearest habitat of beluga whales is off the coast of the polar archipelago of Svalbard to the north of Norway, 3,000 km from France.