Anyone walking in the vicinity of Notre Dame cathedral in Paris on Friday morning might have come face to face with the huge marine mammal on the banks of the Quai de Tournelle.

Could a whale really have swum up the River Seine from the English Channel all the way to the French capital before becoming grounded next the famous cathedral?

Of course not, the whale was in fact a fake and was the work of a group called the Captain Boomer collective whose objective is to raise awareness about the beaching of whales and dolphins.

Along with the fake 20-metre whale there was also a team of fake scientists pretending to examine the beast.

A video was put on social media by one member of the group who warned anyone wanting to swim in the Seine that “there may be others in the water” and joked that the river was not ready for the Olympic swimming.

Naturally the surreal scene meant their stunt was given plenty of media exposure.

“It’s an artistic way of making people aware of the environment,” Bert Van Peel, the founder of Captain Boomer told Le Figaro.

“These hyperrealist sculptures are an immense metaphor for the dysfunction of our ecological system.”

It’s not the first time a “whale” has washed up in an unexpected place in France.

Last summer the same group placed a similar sculpture on the river bank in the Brittany city of Rennes.

And the collective also caused a stir with their “Highway Whale” when it was strapped to the back of a truck and driver around France.

If you want to get a closer look at the Seine Whale, it will reportedly remain beached by Notre-Dame cathedral until early next week.

Real whales do end stranded or washed up on French beaches including 10 near the northern port town of Calais in November 2015.

Sadly by the time animal rescuers reached the scene six of the ten whales had died and only four remained alive and an “exceptional rescue” effort was launched.