The second half of the film is made up almost entirely of a single unbroken 42 minute long take
It took between 15 and 16 takes to shoot the first ten-minute opening scene which is all one continuous shot.
One of Gaspar Noé's best reviewed movies, a fact that, by his own admission, made him somewhat suspicious, as he believes art in general and his movies in particular should be divisive and make the audience uncomfortable.
The cast consists of professional dancers with no prior acting experience, with the exception of Sofia Boutella who is the only professional actress. Although Boutella had the dancing experience that the part required, she hesitated to join the film since there was no script. Director Gaspar Noé encouraged his cast to improvise extensively, with the only limitation that they couldn't reference contemporary things like smartphones, since the story is set in the 1990s.
The film was written, shot and edited in only four months, in order to meet the Cannes Film Festival deadline.
Gaspar Noé got the cast into the dissociative druggy psychosis mindset by preparing a collection of the best videos he could find on the web of people high on crack, high on ecstasy, high on acid. Also the dancers were encouraged to take whatever experiential aspects stuck out to them from the videos and run with them in the film.
In the sequence when we see 'audition tapes' on a TV screen, also various books and VHS covers are in the frame, that provide clues to Gaspar Noé's inspirations: Visible are titles that reference Luis Buñuel, Dario Argento and Romanian philosopher Emil Cioran, famous for his ultra-negative views on life and humanity.
The end credits appear 2 minutes into the film. Additionally, the main credits appear 45 minutes into the film and the title is revealed in the final 8 seconds.
According to Gaspar Noé, the first part of Climax is like a roller coaster, the second like a ghost train.
For the dance scenes, Gasper Noé tried to push his protagonists to stimulate possessed states like those encountered in ritual trances.
Of all the dance scenes in the film, only the first one was choreographed and the rest was the result of the way the dancers chose to express themselves through their own language.
Gaspar Noé stated that the production of this film was the most peaceful he ever had, much contrary to the content of the movie. There were no arguments off set and no use of alcohol or drugs.
According to Gaspar Noé, the reason that "Angie" by The Rolling Stones was used at the end of the film is that he wanted something sentimental and famous to be playing at the end. "Hotel California" by Eagles and other songs by David Bowie and Lou Reed were also considered.
Loosely inspired by a French urban legend from the 1990s. While Gaspar Noe and several other members of the crew claim to recall reading about similar incidents in the news, none can recall any specific details.
Apart from the opening choreographed sequence, everything in the film was improvised.
According to Sofia Boutella, scenes required four hours of rehearsal and over 13 takes each.
The synopsis provided for Cannes Film Festival's 50th Directors' Fortnight section was such: "Birth and death are extraordinary experiences. Life is a fleeting pleasure."
Some psychotic scenes that were choreographed in Possession (1981) inspired some of the scenes in Climax.
According to Gaspar Noé, Climax, once again, represents some of his dreams and nightmares.
According to a 2018 article, director Gaspar Noé doesn't give a damn about the viewer's reaction. He has said he never thinks of an audience when making a film. The focus is always on his own enjoyment.
For the shooting, Gaspar Noé defined some rules such as to film very quickly and in long shots.
According to Gaspar Noé, when he was a kid, it was always sangria he would use to get his fellow classmates drunk.
Inspired by the works of Rainer Werner Fassbinder, Pier Paolo Pasolini, Luis Buñuel, Todd Solondz, and Lars von Trier.
In a 2018 interview about the film, director Gaspar Noé was quoted as saying "Nowadays even the representation of female or male nudity has been demonised. In many ways western societies are going back to the 19th century or towards more repressive cultures with religious origins." He added he sees this trend as paradoxical given the very positive increasing acceptance of LGBT+ identities. " It's much easier for people to be homosexual or bisexual or polysexual or whatever, now people have more sexual freedom. But the representation of sex is becoming problematic."
The long takes were inspired by Victoria (2015), which is a 134-minute-long single-shot movie.
Gaspar Noé's inspiration for the film includes lots of 70's movies such as The Towering Inferno (1974), The Poseidon Adventure (1972) and Shivers (1975).
Received a lengthy standing ovation during its premiere at the Cannes film festival.
The scene where Sofia Boutella's Selva chatacter flips out and tears the curtains off the windows etc. Is a direct refference to Andrzej Zulawski's 1981 classic, Possession , where Isabelle Adjani's Anna character freaks out in a very similar way in a subway whilst carrying groceries.