You might almost think this looks like some practicing heterosexuals riding the Great Gay Gravy Train of 2013

The Cannes prize was given to Mr. Kechiche just hours after masses of French demonstrators poured into the streets of Paris to protest France’s new law allowing same-sex marriage and adoption. While it would be impossible to say whether the protests helped determine the prize at Cannes, the coincidence of the timing was noted.

Le Monde called the festival judges’ decision on the day of the protests “an act of cultural politics that does not lack courage.” The weekly magazine Les InRockuptibles said that the festival “intervened with a perfect sense of timing.”

And Mr. Kechiche told Reuters, “Everyone who is against same-sex marriage or love between two people of the same sex must see the film.” ...

On the Riviera in May, the critics gushed. The graphic sexual encounters were so magnificent, The Guardian wrote, that “they make the sex in famous movies like, say, ‘Last Tango in Paris,’ look supercilious and dated.”

The Hollywood Reporter said the film would surely “raise eyebrows with its showstopping scenes of nonsimulated [sic] female copulation.”

Baz Bamigboye, a critic from The Daily Mail, meanwhile, confessed that he blushed like he had never blushed before, calling the sex scenes exceptionally beautiful. “And I’m not just saying that because I’m a bloke,” he added.

But now the film, directed by Abdellatif Kechiche, is the subject of a multifaceted debate here and abroad that turns on two questions: How to represent the female body and lesbian sex on screen? And who has the right, or at least the authority, to create those images? The debate was set off when Julie Maroh, the 27-year-old author of “Le Bleu Est une Couleur Chaude,” the comic book-novel on which the film is based, criticized the film’s portrayal of lesbian sex as uninformed, unconvincing and pornographic.

“This was what was missing on the set: lesbians,” she wrote in an English translation of a French “communiqué” posted on her blog after the film won the Palme d’Or at Cannes.

Noting that the director and actresses are “all straight, unless proven otherwise,” she said that with few exceptions, the film struck her as “a brutal and surgical display, exuberant and cold, of so-called lesbian sex, which turned into porn.”