The Da Vinci Code director Ron Howard and the book's author Dan Brown are being investigated by Italian state attorneys for religious obscenities.
A complaint has been filed against the 2006 movie by clergymen in the Italian village of Civitavecchia, on the grounds it is "obscene" from a religious perspective.
Howard and Brown feature in the complaint, which names a further eight people.
It is unclear what the unnamed complainants are seeking - but if found guilty the defendants could face jail time of three months.
Asked why the case is being opened a year after the film was released, an official at the Civitavecchia state prosecutor says, "I don't know. Maybe they have just seen the film."
Howard is currently working on pre-production on the film's sequel Angels and Demons.