A French court has banned Lars von Trier's ultra-violent film Antichrist, and the Catholic group who brought the case is also threatening to have Quentin Tarantino's new film pulled from cinemas.
The traditionalist group Promouvoir (Promote) said the US director's Western The Hateful Eight, which is in the running for three Oscars this month, had been "granted its certificate illegally".
It also threatened to take action against the French teen film Bang Gang, one of the hits of this year's Toronto film festival.
It is the third time that the group has succeeded in persuading French judges to ban Antichrist since it won a major prize at the Cannes film festival in 2009.
The same group also managed to have two other sexually explicit films temporarily withdrawn from French screens in the past year.
Gaspar Noe's erotic odyssey Love was banned in July and the permit for Blue is the Warmest Colour, which won the top Palme d'Or prize at Cannes in 2013, was withdrawn in December over its lesbian scenes.
Love has since been re-released with a revised 18 certificate, but Tunisian-French director Abdellatif Kechiche's much-praised love story is still in legal limbo.
Promouvoir argued that the extreme "unsimulated sex" in von Trier's Antichrist, which had a 16 certificate, made it unfit to be seen by minors.
An administrative appeals court in Paris agreed and ruled that the culture ministry had "made a mistake" in its original classification of the film.
Culture Minister Fleur Pellerin was "examining the [court's] decision", her ministry said after the ruling.
The notoriously provocative Danish director, who revels in shocking audiences and censors, admitted when the film was first shown that it was not for the faint-hearted.
Courts previously withdrew permits for the film in 2009, only for the culture ministry to ignore their objections and reissue its certificate.
Antichrist opens with a passionate sex scene between a couple played by Willem Dafoe and Charlotte Gainsbourg, who are so absorbed in their love making they fail notice their toddler falling to his death from a window.
Driven mad with grief, the wife smashes her husband's testicles with a block of wood before drilling a hole in his leg after he passes out.
She later tries to bury him alive before taking a pair of scissors to her own genitals.
Gainsbourg won best actress at Cannes for her performance as the deranged wife, but the film divided critics.
The influential US critic Roger Ebert praised the film for showing "that our fellow men are capable of limitless cruelty, and that it might lead to the obliteration of human hope".
But others were either horror-struck or accused von Trier of trying to wind audiences up.
"I could only watch the film's impossibly grisly final 20 minutes through my fingers," the Guardian's Peter Bradshaw wrote, dismissing it as a "celluloid custard pie [that] has landed squarely in the faces of audiences".
The ban on the film means it cannot be shown in cinemas, on television or on French internet streaming sites unless it gets a new 18 certificate.
Retailers and video stores are also barred from selling or renting DVDs of the film.
Promouvoir has previously tried to sue one of France's most acclaimed novelists Michel Houellebecq, claimed his novel Platform about sex tourism in Thailand, was likely to "corrupt minors".