Vince, a four-year-old white rhinoceros, was found bloodied and mutilated on Tuesday morning by keepers at Thoiry Zoo, some 30 miles west of Paris.
Southern White Rhinoceroses were once nearly extinct, though have since made a comeback and number about 20,000.
There are only around 21,000 white rhinos in the world today, and many were very angry at what had happened. It added that "his second horn was only partially cut, which suggests that the criminals were disturbed or that their equipment proved defective". The poachers likely used a chainsaw to cut off one of the horns, according to a statement from the zoo, which is almost 40 miles west of Paris.
The two other rhinos living in the enclosure, a 37-year-old female, Gracie, and a five-year-old male, Bruno, were unharmed.
The poacher, or poachers, might have forced a door open at the back of the zoo before entering a building where the zoo's three rhinos lived.
"It's possible that the thieves didn't have time to attack the other animals", a source told Le Parisien. A kilogram of rhino horn sold on the black market for almost $54,000 in 2015, according to the zoo.
Vince was born in September 2012 at Burger's Zoo in the Netherlands. It's estimated that 1,100 rhinos were killed in 2016 in South Africa alone, and over 129 have already been killed this year.
Thoiry zoo described the attack as a "heinous act" on its Facebook page. Demand comes mainly from China and Vietnam where it is coveted as an aphrodisiac and for use in substances believed to have healing properties. It's not easy to kill a rhino weighing several tonnes just like that.
"It is time countries outlaw the trade in ivory and horn as I have done in France".