The Bibliothèque Nationale in Paris opened its secret collection of erotic manuscripts and art to the public for the first time in nearly 40 years on Tuesday.

The collection, amassed over 170 years, ranges from manuscripts by the Marquis de Sade to pictures of naughty nuns and randy noblemen.

The trove of licentious literature is known as L'Enfer or "Hell," a name it earned in the 1830s when the library was ordered to isolate its collection of "immoral works."

The public has been unable to see the secret archive, where many works seized by police for immorality were preserved, since 1969.

Among the works consigned to Hell were Voltaire's La Pucelle (The Maid), a comic poem that created a scandal in 1762 and Thérèse Philosophe, a 1748 bestseller about the initiation of a lustful young woman.

There are works by Apollinaire, Louÿs and Bataille and many authors who chose to remain anonymous.

Also on display are pamphlets illustrating the supposed depravity of the Queen, Marie-Antoinette and the Royal Court, which circulated just before the French Revolution.

More than 350 works from the secret archives went on view Tuesday.

The National Library believes acceptance of sex and sexuality has changed to the point where the works will be accepted on public display — but only to patrons over the age of 16.

One Metro station is even offering a teaser for the exhibition, with erotic engravings plastered on its walls.