Celebrities aren’t generally told what they can and can’t do, but that’s about to change at the Cannes film festival, where organizers say red carpet selfies will be strongly discouraged this year.

The reason is supposedly logistical. When stars stop to pose for themselves on the red carpet, it slows down a procession that’s already sluggish with so many photographers snapping shots and journalists asking questions. But festival director Thierry Fremaux couldn’t help but editorialize un peu in the process of his announcement.

“It’s a practice that’s often ridiculous — extremely ridiculous — and grotesque,” he said, before adding, “but we don’t want to prohibit it.”

This is especially rich considering that Cannes, for all its intellectual hauteur, was once the world capital of ridiculous — an epicenter for showbiz preening and over-the-top publicity stunts.

Sure, the festival is known for its edgy, artsy films. But it’s also the place Jerry Seinfeld dressed up as a bumble bee to promote “Bee Movie”  in 2007. And where, the following year, Jack Black showed off his martial arts skills while a whole crew of panda-costumed extras paraded behind him down the red carpet in support of “Kung Fu Panda.” Sacha Baron Cohen rode a camel for “The Dictator” screening after having his fake guards point machine guns (that were props, let’s hope) at the press, and the promotion for Jim Carrey’s “A Christmas Carol” involved covering the red carpet in snow — in May. Talk about slowing things down.

And those are just the more PG examples from recent years. B-, C- and D-list starlets historically used the festival as an opportunity to make headlines by showing some flesh, sometimes faux-accidentally — a little nip slip goes a long way in the gossip rags.

And sometimes not so-faux-accidentally: Back in 1954, actress Simone Silva showed up topless, cupping her breasts with her hands, to pose with Robert Mitchum in 1954, and Cohen wore a barely there fluorescent thong-swimsuit-sling thing — for lack of a better term — to promote “Borat” in 2006. Arnold Schwarzenegger wore slightly more clothing while promoting the documentary “Pumping Iron” in a banana hammock in 1977.

The director and actors of “The Misfortunates” bicycled in the buff in 2009 to promote their film, which, if not tasteless, is at least extremely uncomfortable. And as recently as last year, the fame-clinging Lindsay Lohan posted a selfie of herself at Cannes where she appears to be topless (although the cropping leaves something to the imagination).

This is all self-promotion at its most desperate. Selfies, while admittedly silly, are actually a more inconspicuous form of PR. Over the years, there has been no shortage of attention grabbing that slowed down the red carpet walk. There was an elephant, a contortionist and a vulture, to name a few. You could also point to plenty of grotesque vulgarity. But selfies? Those are completely beneath Cannes.

How exactly Cannes organizers intend to “slow down the contemporary practice” of selfie-taking, as Fremaux described it, is unclear. Who wants to be the one to snatch Jane Fonda’s smartphone out of her hands? Or tsk-tsk at Cate Blanchett? Ever-more disdainful festival President Pierre Lescure hinted that they may appeal to vanity and shame, snarking at the press conference that “Honestly, you’re never as ugly as on a selfie, right? So. . . ”

Clearly Lescure just has the best interests of the stars in mind with this new “campaign.” Still, we doubt Kim Kardashian is rushing to stop the presses on her selfie-filled coffee table book “Selfish.”