A beluga whale has been spotted in France's River Seine, and officials are now deciding how to save a mammal more suited to cold Arctic waters.
They say the animal is currently near a lock at Vernon, about 70km (43 miles) north-west of Paris.
Experts are puzzled as to why the whale has strayed so far south from its natural habitat.
"The challenge now will be to help feed it, and try to accompany it towards the ocean," Lamya Essemlali, the head of environmental group Sea Shepherd France, was quoted as saying by the Reuters news agency.
She said taking the animal out of the water was out of the question as it was too risky.
Pictures have emerged showing the whale swimming slowly in the river.
The officials have not reported on the size of the animal, but an adult beluga can grow to more than four metres (13ft) in length.
In 2019, a dead whale was found in the River Thames near Gravesend, UK officials said.
This came just weeks after a humpback whale seen swimming in the same stretch of water had died. It was thought to have found its way into the Thames because of a navigational error, possibly during high tides.