Paris has claimed London is a "suburb" of the French capital, which is far safer than its rival, creates more start-ups, is more attractive for families and brings in more tourists, reports The Telegraph.
Anne Hidalgo, the deputy mayor of Paris, made the claims as a stinging Gallic response to British figures suggesting that London may have overtaken the French capital as the world's most popular tourist destination.
The 54-year-old, who is the favourite to succeed Bertrand Delanoë, her fellow Socialist, in March's mayoral elections, also fired a broadside against London's "boastful" mayor, Boris Johnson.
"London is in some ways a suburb of Paris", she told The Telegraph and others reporters with the Anglo-American press association of Paris.
"Like it or not, while London may have attracted more visitors around the Olympic Games, Paris remains the number one world tourist destination, even if we only include foreign visitors and not national ones."
Her comments came after figures showed the number of foreign visitors to London surged by almost 20 per cent last summer to a new record of 4.9 million between July and September.
"For the first time in history, the city (of London) is on course to welcome over 16 million overseas visitors in one year," the British capital's tourism agency London & Partners said in a statement.
This led French right-wing daily Le Figaro to declare: "London dethrones Paris", basing its claim on 2012 figures in which 15.9 million foreigners visited the City of Lights.
Boris Johnson weighed in, saying: "These incredible figures prove that London is without doubt the greatest city on the planet. With so many fascinating museums, the best theatre scene in the world, more green space than any other European city, numerous top sporting venues, a low crime rate and much else besides, it's no wonder that people from all over the globe are flocking to London in record numbers."
Mrs Hidalgo retorted: "Boris Johnson boasts about the merits of London in different way to the French, and Parisians.
"London aggressively sells itself, often in a way that goes beyond the truth. We are more rational in our communication when speaking about Paris' strengths."
Her office said that in 2012, the city of Paris, which does not include attractions in the wider Paris region such as the Palaces of Versailles and Fontainebleau, attracted 29 million tourists of all nationalities.
Meanwhile, Greater London, which covers an area ten times larger than the city of Paris, welcomed 27.6 million domestic and international tourists," it added.
Miss Hidalgo accused her Right-wing rival for the mayor post, Nathalie Kosciusko-Morizet, of unpatriotic "Paris bashing" for citing the figures as proof the Socialists were failing the capital.
Listing Paris' "strengths", she said: "Paris is a safer city than London. There are four times less crimes in Paris than in London."
Read more of this report from The Telegraph.