The traditionalist Promouvoir (Promote) lobby group wants the film version of the last of E. L. James' trilogy on a sadomasochistic love affair banned for under 12s.
The blockbuster, starring Dakota Johnson and Jamie Dornan, can be watched by anyone in France even though only over 18s can see it in Britain.
US censors gave it an R rating, meaning under 17s must be accompanied by a parent.
"It's crazy that this film should be seen by seven-year-old children. It has to be banned for children under 12," the group's lawyer, Andre Bonnet, told AFP late Thursday.
"The courts must judge if showing an adult film -- especially when it is about this sadomasochistic relationship -- is right for children," he added.
The group has scored several court victories by using a clause in the French film classification rules which allows films to be pulled from cinemas if they might affect "the emotional development of children".
Gaspar Noe's erotic odyssey "Love" was banned by the courts in 2015 and the permit for "Blue is the Warmest Colour", which won the top Palme d'Or prize at the Cannes film festival in 2013, was also withdrawn the same year over its lesbian scenes.
While "Love" was re-released with a revised 18 certificate, Tunisian-French director Abdellatif Kechiche's much-praised love story was left in legal limbo.
It prompted the French culture ministry, which has generally overturned the bans, to order a rethink of the rules.
Von Trier, the notoriously provocative Danish director, who revels in putting audiences and his actors through the wringer, admitted that "Antichrist" was not for the faint-hearted when it was first shown.
It 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.
Promouvoir also tried to have the age classification for the first of the E. L. James' movies, "Fifty Shades of Grey", raised when it was released in 2015, but without success.