Poachers broke into a zoo an hour's drive west of Paris and slaughtered a rhinoceros and cut off his horn, reports the London Evening Standard.
It is believed to be the first incident of poaching from a living animal in captivity in Europe.
The five-year-old male was found with three bullets in his head and his horn severed off at the Thoiry safari park near the French captial on Tuesday morning.
It is thought that the one or two of the poachers forced their way through a gate into the park on Monday night before breaking into the building where three rhinos live.
A source close told Le Parisien newspaper that it is believed the poachers were targeting all three animals but were disturbed and did not have time to kill the other two animals.
According to local media a rhinoceros corn is worth around 40,000 euros or 34,000 pounds on the black market.
The white rhino arrived in the park in 2015.
The white rhinoceros was called Vince and was one of the most popular attractions at the zoo, said park director Thierry Duguet.