Medics revealed a 44-year-old woman was infected with the virus on a family trip close to Nice in September.
She went to A&E in the UK with a three-day fever, pains and a rash but later made a full recovery.
Dengue is most often found in tropical countries like Vietnam and Brazil.
But global warming means the mosquitoes that spread the dengue virus are comfortable coming further north, with cases set to rise in future.
French health officials warned of an outbreak in the country’s south last year.
Dr Owain Donnelly, from London’s Hospital for Tropical Diseases, said the spread of the illness is “rapidly changing”.
He said: “Hotter temperatures and more rainfall, and increasing global trade and tourism, mean we may see more parts of Europe with the right combination of factors for dengue outbreaks.”
The virus causes fever, headache, muscle and joint pains, vomiting and a blotchy rash.
It usually heals on its own but around five per cent of cases are severe and can be deadly.
Around 50million people per year are infected with dengue, mainly in Asia, Central and South America and the Caribbean.
It does not spread between people but is carried by the Asian tiger mosquito, which is on the rise in Europe.
Speaking at the European Congress of Clinical Microbiology & Infectious Diseases, Dr Donnelly added: “Physicians should consider testing for dengue if patients live in or have visited countries even where it is not widespread.”