There are dozens of them. Kids take them out on leads, and even carry baby monkeys around in nappies. But these animals can be very dangerous. Imported illegally through Spain from Gibraltar, Morocco or Algeria, the Barbary apes are known for their powerful limbs, sharp teeth and short tempers.
Veterinary experts say they can be turned into frightening and effective weapons.
Removed from their natural habitat, they can become highly aggressive. They bite, and their favoured method of attack is to hurl themselves at people's heads. Police believe as many as 500 Barbary apes may have been smuggled into France in the past two years. We've heard of monkey fights being run in tower block basements. Ms Bomsel said the museum had received dozens of telephone calls from owners wanting to know how to deal with violent monkeys, or how to get rid of them.