A jury led by Steven Spielberg  and packed with fellow Oscar winners Nicole Kidman, Ang Lee and Christoph Waltz among other luminaries was to deliberate on Sunday in seclusion at a villa in the hills above Cannes.
Critics swooned over Kechiche's coming-of-age tale about a girl's first love, an older woman.
"La Vie d'Adele - Chapitre 1 & 2" ("Blue is the Warmest Color") is a poignant tale of love and sexuality centered on a 15-year-old girl named Adele, in a breakout performance by Adele Exarchopoulos, and her lover Emma (Lea Seydoux).
“Sure to raise eyebrows with its show-stopping scenes of non-simulated female copulation, the film is actually much more than that: it's a passionate, poignantly handled love story,” a Hollywood Reporter critic told AFP.
“Remarkably, though, the explicit scenes never really feel pornographic, especially since the film isn't about titillation or arousal.”
The film topped critics polls in trade journals Screen International and Film Francais, as well as London bookmakers' rankings.
But reviewers wondered whether the jury would shy away from rewarding its lengthy depictions of on-screen lovemaking -- among the most explicit in Cannes competition history.
Kechiche told journalists it was not his intention to make a film about gay rights, in the context of the debate over same-sex marriage which was legalized in France this month, and said the depictions of sex were aimed at depicting beauty.
“We hope that in the scenes the idea of beauty will emerge. I think sensuality is more difficult to film and capture onscreen,” he said.
The film is loosely based on a 2010 graphic novel of the same English title.