Director Jacques Audiard, singer Camille and actor Karla Sofia Gascon revealed to AFP the secrets behind the film that has created the biggest buzz so far at this year's festival.
- Mexico-on-the-Seine -
"Emilia Perez" is the story of a notorious Mexican drug lord who transitions to a woman, in the process escaping a life of narco violence.
But it was largely filmed 9,000 kilometres (6,000 miles) away, at studios in the Paris suburb of Bry-sur-Marne.
"It would have been a challenge to shoot in Mexico. I did a lot of location scouting there but there would have been too many constraints," said Audiard.
Ultimately, using a studio set "allowed me to shoot exactly the images I wanted, without being contaminated by reality", he explained.
The decision did afford Hollywood stars Zoe Saldana and Selena Gomez the opportunity to explore a seldom visited suburb of the French capital.
Only one indoor scene, and one shot of a procession in a village, were actually filmed in Mexico.
"For me it is not a documentary," said Audiard. "I read a lot of Mexican literature, I listened to Mexican music, I watched a lot of Mexican films.
"It's really the result of imagination, and the way I feel things... I have a very poetic relationship with Mexico."
'Love languages'
"I barely speak any language other than French -- and even then..." joked Audiard, whose film is mainly in Spanish.
Audiard is no stranger to shooting in foreign tongues, winning the Cannes festival's top prize Palme d'Or in 2015 with immigrant saga "Dheepan", which is largely in Tamil.
He has also previously made a movie in English, with his 2018 Western "The Sisters Brothers", but felt Spanish was the more authentic option for a tale set in the world of violent Mexican narco gangs.
Shooting in an unfamiliar language allowed "a whole poetic field to open up for me", he said.
French singer Camille, who wrote the film's songs, said she relished the challenge of writing in Spanish.
"The music of people comes from their languages. To immerse yourself in a language is to immerse yourself in music," she said.
"I studied Spanish at school and the opportunity to sing and write in Spanish, as someone who usually sings in French or English... I was so happy," Camille added.
"I love languages... If someone asks me to write a film in Chinese, I can't wait."
'More fun'
Spanish trans actor Karla Sofia Gascon, who began her transition six years ago at 46, is a revelation in the film's central role of Emilia.
But at the start of the film she also plays the male drug lord Manitas, before he undergoes surgery.
"I'm not going to lie -- for me, playing the role of Manitas was a lot more fun than playing Emilia Perez," she said.
"Playing a Mexican drug dealer, with a different voice than mine, and singing... Audiard didn't initially want me to play the male character," she added.
Gascon said she had to convince her director by sending him videos and photos for months, "until one morning he called me and said 'the two characters are yours, leave me alone'."
According to Audiard, Gascon's anecdote is slightly too modest.
"She exaggerates just a little bit. It was very easy to convince me!" he said, smiling.
