Unlike the costume drama it appears to be, “Quills” is decidedly free of the lavish sets and pretentious history lessons that grind other period pieces like it to a screeching halt.

Although ripe with expensive costumes and French accents with varying degrees of thickness, “Quills” is a dark, often dirty film that explores the amoral pervert in all of us.

Set in the late 18th century in the aftermath of the French Revolution, the story is a fictional account of the last days of the Marquis de Sade (Geoffrey Rush). Those unfamiliar with the Marquis’ library of work will recognize his impact in today’s romance novels and pornography. While his writings might seem tame by today’s standards, the Marquis is one dirty fellow, and without him we wouldn’t have the vast vocabulary we now have to describe one’s private parts.

We first meet the Marquis in an asylum, where he had been locked up during the Revolution for his former crimes. Even under lock-and-key, however, the Marquis is allowed by the asylum’s director (Joaquin Phoenix) enough quill pens and ink to purge his filthy mind. It is with the undercover assistance of one of the asylum’s resident laundry maids, Madeleine (Kate Winslet), that allows the Marquis to get published. At the start of the film, all of France’s lower class is being treated to secretly published and distributed novels about the age-old meeting between the pizza guy and the lonely mistress.

This catches the eye of Napoleon, who refuses to allow such baseness to be read by his kingdom. So, he sends a doctor (Michael Caine) to keep watch over the asylum and, particularly, the Marquis.

“Quills,” expectedly, develops into an examination of sexual subversion and the freedom of expression. As the plot progresses, we see the Marquis risk his sanity and whatever freedom he has to ensure his sensual tales are read. And whatever the men of science and religion do to keep him from unleashing his style of pornography, notably by taking away his quills, we see the Marquis conquering them with showing how much art imitates life.

Under a lesser hand, the sexual perversion of “Quills” would have been wasted on insane asylum sodomy and necrophilia. But “Henry and June” director Philip Kaufman brings a sensuality to a tale that otherwise would have been mired in filth.

The actors keep the production a fine one, too. But overall, “adequate” would be the best word to describe the performances. On top, as usual, is Rush, who infuses his character with just the right amount of perversion, genius and stubbornness. He plays the Marquis with spirit and vengeance, and he’s just unlikable enough to make the audience believe he’d use the word “oyster” to describe a lady’s unmentionables.

The rest of the actors merely serve to keep the film from going under like so many torture devices. Phoenix, as the asylum’s director, plays the typical man of the cloth who has doubts about his convictions. Michael Caine, as the doctor sent to keep close watch over the Marquis, virtually plays himself playing the bad guy as only he could. Winslet continues her wonderful series of portrayals as the girl who gets raunchy with older, dirty men (begun with her and Harvey Keitel in Jane Campion’s “Holy Smoke”).

To its disadvantage, however, “Quills” tries as hard as it possibly can to make sure we see the parallels between art imitating life both today and yesterday, and the importance of freedom of expression.

Would the Marquis approve of such hard-taught lessons in his titillating and alluring tales? I think not.