Francis Cloris, a sub-prefect in the western Vendee department, said the results of tests delivered late Friday on the animal that died on November 10 in the town of Fontenay-le-Comte had shown it had contracted rabies.
Cloris said there was no danger of transmission to humans, though 14 people who had been in contact with the cat, the pet of a pharmacist, were being monitored by doctors.
These included the vet who had examined the cat two days before it died and was bitten.
The animal "did not go out much, and had never been abroad," Cloris said. "But it frequented the loft and the roof of its owners' home, where it could have been infected by a bat."
Further tests were being carried out in an effort to identify the particular rabies virus and how it was transmitted to the cat, he said.
The last case of rabies to occur in France was in 2004 in a dog, which was already carrying the disease when it entered the country from Morocco.
Departmental veterinary chief Didier Boisseleau said rabies carried by dogs had been eliminated from France decades ago, and the virus transmitted by foxes at the beginning of this century.
Bats were still found with rabies, but it was very rare for them to pass it on to domestic animals, Boisseleau said.