With its talking cats and wandering samurais, Japanese manga is taking France's booming comic-book market by storm, challenging home-grown icons like Asterix as young readers lap up the eastern fare.

"In every French home you'll find a few "bande dessinee" albums, it's a real part of our culture," said Nicolas Finet, an organiser of the annual International Comics Festival, a four-day jamboree that opens Thursday in the western French city of Angouleme.

Last year alone, more than 4,000 new comic book titles hit the shelves in France and French-speaking Belgium and Switzerland -- a three-fold increase since 2000 -- with more than 40 million copies sold, according to market researchers GfK.

But in recent years, characters with names like "Kakashi" or "Mamoru" have been jostling for elbow room with their French-sounding counterparts, with manga now making up 40 percent of all comic book sales in France.

By some estimates France is now the biggest market for manga outside Japan, and Finet says the French market has "fundamentally changed" as a result.

"Ten years ago, European authors were basically alone, save for a few US titles. Now they are being squeezed."

In a nod to the changing times, the latest Asterix album has the plucky hero warding off a threat from a locust-like "Nagma" -- an anagram of manga -- as well as from a devious "Tadsylwine", an anagram of Walt Disney.

France's publishing giants, who saw the manga wave coming, have managed to salvage their overall market share by licensing and distributing most of the Japanese titles sold in France.

So it is the authors who face the biggest challenge, as manga fans increasingly desert traditional Franco-Belgian comics.

But some French-speaking authors are already trying to learn from manga -- its real-life tempo and cinematic visual codes, with epic stories drawn out over several volumes -- and the first home-grown manga started appearing in France last year.

In Paris a school called Eurasiam was set up in 2005 to turn French comic artists into genuine "mangaka", and a Belgian artist, Vanyda, won the US magazine Publishers' Weekly's best manga award in 2006 for her album "L'Immeuble d'en Face" (The Building Over the Road).

"It is still early days, but things here have started to change," said Finet, who sees manga's success as "a sign the world's centre of gravity is shifting eastwards".

"Since the 1990s, teenage readers have felt the need to go looking for new points of reference, to break with the older generation that looked more towards America."

"Manga's just cooler," shrugged 20-year-old medical student Victor Leloup, as he thumbed through the Japanese titles -- ranging from robots and space heroes to gritty social realism -- in a large Paris bookstore.

European comics also span from moody detective fiction to fairy-filled fantasy -- even politics, with one best-selling title lampooning the right-wing presidential candidate Nicolas Sarkozy -- but their typical reader is still male, in the 25-35 age bracket.

One of manga's big strengths is to cater to a bewildering variety of niches: businessmen, housewives, grandparents, and teenage girls, who are the fastest growing market area for comics in Europe.

Another sales argument for impoverished teens: the small, black-and-white paperbacks are around half the price of a typical French comic, generally lavishly-illustrated glos