Paris, France: A rare manuscript by the 18th-century libertine Casanova, recalling his sexual conquests and many adventures, has entered the collection of France's National Library, the institution said on Thursday.

The French manuscript of "The Story Of My Life" forms the core of 3,700 precious pages acquired by the state library, an official told AFP, calling it the collection's "biggest heritage acquisition" ever.

Specialists say it is the only surviving manuscript by Casanova, a Venetian adventurer and womaniser whose name has become synonymous with seduction due to his own accounts of his affairs, written in French from the 1780s.

The museum said an anonymous patron spent seven million euros ($13 million) to help the library acquire the manuscripts from the heirs of a German publisher who acquired them in the 19th century.