The Asian predatory wasp could threaten bee-keepers' livelihoods
France faces an invasion of Chinese hornets that could hasten the decline of the honeybee population.
The wasps, known by their scientific name Vespa velutina, could also threaten bee-keepers' livelihoods, researchers say.
They have spread rapidly in south-western France - a region popular with tourists - and could reach other European countries soon.
The 3cm-long insects are recognisable by their orange heads and yellow feet.
Researchers think they probably arrived in France on a boat carrying ceramic goods from China in 2004.
The most recent study recorded 1,100 nests across the country. The hornet is now firmly established near Bordeaux and has advanced as far north as parts of Brittany in north-western France.
"More and more of them are coming and they're colonising France," Quentin Rome, a researcher at the National History Museum in Paris, told Reuters news agency.
"They multiply quite quickly, and they settle in a new department (administrative division) every year."
V. velutina has not yet reached other European countries, but will probably spread across the continent, he added.
Six people needed hospital treatment last week after being stung near a nest in the Lot-et-Garonne department in south-west France. Local authorities are warning allergy sufferers to be on their guard.
The hornets are no more aggressive or dangerous for humans than their European cousins. But the size of their colonies - with nests measuring up to one metre in height - meant the risk of attacks was higher, said Mr Rome.
Denis Thiery, a researcher at the French National Institute for Agricultural Research, told Le Parisien newspaper: "According to our studies, they are able to settle in 50% of the country.
"The European hornet is no match for them, with only a few hundred individuals per nest compared to several thousand for the yellow-footed hornets. They do sometimes fight, but it's a losing battle."
Bee-keeper Francoise Romanzin said there had been a marked rise in attacks by Asian hornets on beehives in August.
"The problem of the Asian hornets is not the worst problem for bee populations but it adds to the difficulties bee populations are already facing," Ms Romanzin said.