Police arrested a teenager suspected of posting his own translation of the latest Harry Potter novel on the Internet weeks before the official French release, the book's publishers said on Wednesday.

The 16-year-old schoolboy, from the Aix-en-Provence region in southern France, was taken into custody by a police anti-counterfeiting unit and later released, said a spokeswoman for the Gallimard publishing house, which handles the French editions of the novels.

Concerned that such acts of counterfeiting are threats to basic authors' and creators' rights, (author J.K. Rowling and Gallimard) immediately agreed to support the investigation as it was launched, spokeswoman Marie Leroy-Lena said in a statement.

It is not a young person or a fan we are talking about here -- these are organized networks that use young people, she told Reuters by telephone.

For the moment there is an ongoing investigation, and neither Gallimard nor Ms. Rowling has filed an independent lawsuit.

The newspaper Le Parisien reported earlier that the book's first three chapters appeared on the Web just days after the English-language edition of Harry Potter and the Deathly Hallows went on sale in late July. The paper said boy was arrested on Monday.

Police were not available for comment.

The official French language version of the book is scheduled for publication on Oct 26.

The seventh volume of the Harry Potter saga is the fastest selling book in history, publishers say, with about 11 million English-language copies sold in the first 24 hours.

Many French stores are selling the English-language version.