In 2009, more than 400 people put their lives on hold and entered a facsimile of a Soviet research plant, where they conducted experiments, gossiped, fell in love, endured arrest, suffered punishment, conceived children and betrayed one another.

They lived for two years in a parallel universe contained in a sealed set in Kharkiv, in northeast Ukraine, where the Soviet physicist Lev Landau worked in the 1930s. A biopic about the Nobel laureate and Russian Jewish genius — begun by the Russian director Ilya Khrzhanovsky in 2005 — expanded into a massive role play and interactive spectacle dramatizing the sequestered life of the totalitarian state’s scientific elite between 1938 and 1968.

DAU,” which draws its title from the nickname of the acclaimed scientist, was set to open Thursday across three sites in Paris but was delayed pending further negotiations with the city. The “ongoing experiment” comprises 13 feature-length movies drawn from 700 hours of footage. The film has elicited comparisons to “The Truman Show,” “Big Brother” and “Blade Runner.” It has something in common with Secret Cinema, which stages immersive theater experiences in impromptu spaces.

Comparisons falter, though, in the face of the sheer ambitions of the artwork. Those involved in its long-secret making — overseen by the 43-year-old Khrzhanovsky — claim it could present “the most authentic portrayal of life in the Soviet Union ever created.” What makes the film so authentic also makes it troubling, some fear, warning that the project — in playing with the boundary between life and art, between past and present — ended up on the wrong side of an ethical line.

Writing in the Daily Telegraph on Thursday, Albina Kovalyova, a documentary director and producer who said she had been a casting assistant for the project, wondered whether Khrzhanovsky, by developing such a precise model of Soviet totalitarianism to condemn it, “may have become a despot himself and overseen behaviour that crossed the line from fictional abuse to the real thing.”

She recalled a former prison director recalling how he had “roughed up a woman who had been stripped naked in a cell" — violence that he was moved to commit “for the sake of the project.” The former casting assistant claimed to have had a breakdown after “watching one scene that showed experiments being performed on babies with Down syndrome.” Khrzhanovsky, told her the children had not been mistreated, she wrote, but she continued to feel “cruelly manipulated.”

“No children were harmed during the scenes which depicted fake experiments being carried out on them," a spokesperson for “DAU” said in a statement. “All children in the Institute were accompanied by their parents and/or qualified caregivers at all times, to ensure their safety and wellbeing.”

A trailer for the film says the participants “became open to new discoveries, personal and scientific.”

“They traveled through three decades, ending up in 1968, changed forever,” it declares.

Only someone who was a child when the regime ended would want to re-create that world, or have the energy and imagination to do so, said Ian Christie, a professor of film and media history at Birkbeck College, University of London.

Christie, an acquaintance of Khrzhanovsky, said the product could be “spectacular.” A preview in the French newspaper Libération was more skeptical, calling the project “as ambiguous as it is vain” and claiming that it enjoyed a budget as big as the gross domestic product of Belize.

There was no script, and few of the participants were actors by trade. Teodor Currentzis, the Greek-Russian conductor, took on the role of Landau, and the actress Radmila Shchyogoleva played his wife. Hundreds of everyday people joined the set, which became known as the Institute.

"I will probably never find myself in such a situation ever again,” a resident of Kharkiv told the Moscow Times in 2013.

Viewers, who must be older than 18, will spot familiar faces, including that of artist Marina Abramovic. They will hear the voice of actor Willem Dafoe.

Instead of a ticket, a “visa” grants entry, either for six or 24 hours, or for unlimited access. Lengthier stays require visitors to complete a psychometric questionnaire that, promotional materials promise, will “enable our algorithmic system to tailor your DAU visit specifically for you.”

Production unfolded in secret, stoking speculation as grainy photos bounced around the Internet. Few journalists were allowed any access.

The snapshots that did emerge were eerie. Michael Idov, in a GQ story in 2011, called Khrzhanovsky, the son of the famed Russian animator Andrei Khrzhanovsky, “unhinged.” Questions mounted about whether the film would ever find an audience, even as it kept Cannes buzzing. Khrzhanovsky had earned critical acclaim for his 2004 film “4,” the poster for which shows a close-up bare female breast.

“Armed with total creative control, he invaded a Ukrainian city, marshaled a cast of thousands and thousands, and constructed a totalitarian society in which the cameras are always rolling and the actors never go home,” wrote Idov, who gained access to the Institute as a “visiting foreign dignitary,” a role for which he wore a three-piece suit and a fedora.

Entrance to the site, which occupied Kharkiv’s old outdoor swimming complex, required period costumes. Once inside the 12,000-square-meter space, where residential buildings stood among science labs and a cafeteria, participants ate period food, which they purchased with Soviet rubles.

Modern equipment was prohibited; even mention of advanced communications technology was verboten. Women were reportedly left to use Soviet-model cloth tampons. Participants were encouraged to inhabit midcentury social structures and to take up leisure activities of the era.

Life on set was embraced with such gusto that 14 children were conceived at the Institute.

The executive producer, Martine d’Anglejan-Chatillon, sought to put to rest the suggestion that some of the material was pornographic by telling Screen Daily magazine, “When people live together for three years in a confined space, they have lots of sex. I can report that." But she also said the footage showed "people having breakfast, people cleaning cars, people driving down the streets or cooking or all sorts of things. There is no hierarchy there in the value of their actions.”

So intent was the director on duplicating the midcentury Soviet experience, Kovalyova recounted, that he installed waste pipes of the precise dimensions as those from the era so that the toilets would emit the right flushing sound. Off-kilter staircases and unlit corridors were designed to “heighten the sense of claustrophobia," she wrote. Monotonous string music blared from loudspeakers “in an apparent attempt to make cast members feel tense.”

The experiment began without secret police, according to James Meek, a novelist and former Guardian correspondent in Moscow who got a glimpse of the project during postproduction in London.

But the Institute gave rise organically to a “repressive apparatus” in which neighbors denounced one another for breaking the research center’s rules, he wrote in an account in the London Review of Books. Soon, midnight arrests were landing participants in prison. There, they shared cells with actual criminals who were recruited by Khrzhanovsky from the real prison in the Ukrainian city of 1.4 million people.

The shoot ended when the director ordered the demolition of the Institute in November 2011. According to Russian media accounts cited by Meek, Khrzhanovsky enlisted genuine Russian neo-Nazis to “storm the set, destroy it and performatively enact a massacre of its staff.” A party boasting an open bar followed, drawing locals who thought they were there for a nightclub opening.

“I don’t think there’s been anything like this,” Christie, the film scholar, said in an interview with The Washington Post. “It’s on a scale that we’ve never seen before.”

The professor said he was invited to meet Khrzhanovsky several years ago, when the director was working in London during the postproduction phase. He entered an unremarkable building in central London and, on the inside, found a reproduction of a Soviet interior. “This wasn’t for filming — it was for living, working and meeting people,” Christie said. “It was like stepping into the past.”

The attempt to rediscover a lost world, one that was never fully known to Khrzhanovsky’s generation, is by nature a commentary on modern Russia, Christie said, where "all the new trappings” have not erased “what is the same physical structure.”

“It’s like two worlds coexisting,” he said, and “DAU” beckons viewers to stand at their union.

The film was initially slated to premiere in Berlin as the first stop in a three-city tour, but authorities objected to plans to build a reproduction of the Berlin Wall as part of the opening. It is still expected to move on to London after it finishes in Paris Feb. 17.

The “extraordinary secrecy” in which Khrzhanovsky works tends to breed rumors, Christie observed, saying he would not want to amplify accusations of mistreatment at the Institute.

“I’m sure things happened inside this closed world — things that would not be very easy to understand from the outside," he said. “Ilya was serious about creating an alternate world.”