Boulogne-sur-mer, France • Scores of policemen, some armed with shotguns, are hunting a mysterious big black feline spotted in northern France, officers said.

The operation was launched Wednesday near the town of Boulogne-sur-Mer after several panicked people first raised the alarm on seeing what they described as a “panther” about 1.2 metres long on a popular beach.

Some 80 officers and a helicopter were immediately deployed on a search, and the beach was closed for a day, but they failed to find their quarry.

Belgian tourists and residents then reported seeing the black beast on Friday, and on Saturday people out strolling saw it in the middle of a cornfield.

Police finally spotted it through binoculars.

“It’s a black or dark feline, fairly hefty, not very high but pretty long. It’s not a panther. It’s a big cat with at least a metre in length,” one officer said.

He added that it appeared to disappearing into forested areas, frustrating efforts to catch it or kill it.

The type and origin of the big cat was unknown. A circus in the area denied having lost any animals.

The sightings recalled those of a similar beast seen in the nearby town of Touquet in 1986 which was never found despite the efforts of 50 officers and a helicopter.