Connoisseurs of cinema consider the late Henri-George Clouzot to be one of the finest masters of the medium.

In France, where Clouzot was born in 1907 and died 70 years later, he’s thought by many to be the greatest filmmaker the nation ever produced.

The films Clouzot wrote and directed during the Second World War and in the two decades thereafter – most notably Le Corbeau (The Raven), Quai des Orfèvres, The Wages of Fear and Les Diaboliques (The Devils) – earned him international acclaim.

His precision handling of suspense thrillers that plumbed the depths of the dark side of human psyche earned him the nickname “the French Hitchcock”, and indeed Hitch himself considered Clouzot a serious rival, so much so he made Psycho to outdo Les Diaboliques, the rights to which novel were acquired by Clouzot just hours before Hitchcock put in a bid.

Clouzot’s two decades as France’s reigning king of cinema came to an abrupt end in 1964, however, during the making of L’enfer. At the height of his

creative powers, Clouzot had returned to filmmaking four years after receiving an Oscar nomination for the film he made with Brigitte Bardot, La Vérité (The Truth).

Now, fuelled by his ongoing battle with depression, he wanted to make a film about a middle-aged man driven mad by his jealously of his beautiful young wife, and he was duly given carte blanche to do so. Then, three weeks into filming what was widely anticipated to be the cinematic event of the decade, the project fell apart. Afterwards, Clouzot completed just one more film, 1968’s La Prisonnére, before retiring from filmmaking for the last 11 years of his life.

Despite the messy end to L’enfer, the images Clouzot committed to film in that short period of shooting are thought to be extraordinary. Unfortunately, they’ve only ever been seen by a handful of people – the cans of film kept locked away from everyone else by Clouzot’s loyal and protective second wife and widow, Inés de Gonzalez.

Meanwhile, in the intervening 35 years they, and the story of what went wrong with L’enfer, have become the stuff of film legend. And things might have stayed that way were it not for the efforts of French film conservationist Serge Bromberg, who convinced Gonzalez to allow him access to the surviving footage of L’enfer.

Working with entertainment lawyer Ruxandra Medrea, Bromberg has used the Holy Grail of lost film footage as the basis for an excellent documentary, fully approved by Gonzalez, titled Henri-Georges Clouzot’s Inferno.

“I visited Mrs Clouzot and we had discussed the footage of L’enfer,” says Bromberg, whose film premiered at the Cannes Film Festival in May. “My intention was simply to see these lost pieces of film. I have spent the last 38 years of my life searching for lost films. That is what I do.

“At that point I had no thought of using them to make a film. When I left, Mrs Clouzot decided to see me down to the first floor and we got stuck in the elevator. So we talked for two hours and we found that we had the same idea about what could be done with the footage.

“Eighteen months later,”

Bromberg continues, “I finally saw the footage, all 185 cans of it. And it was amazing, beyond words. It was bigger and better than the legend. So I decided the images should be seen in cinema, which is what they were meant for in the first place. No one can say what the film would have been like if Clouzot had finished it, so I didn’t want to try to reconstruct it. I just wanted to tell the story of the search for the footage and of the making of L’enfer, and I wanted to show some of Clouzot’s amazing looking film.”

Bromberg’s film mixes interviews with key cast and crewmembers – future director Costa Gavras and then debuting actress Catherine Allégret among them – with newly performed script-readings of a number of scenes and a good deal of the 15 hours of footage Clouzot shot.

The stuff Clouzot got in the can – test shots of psychedelic images using the latest visual art and special effects innovations intended to represent the deteriorating psyche of the film’s jealousy wreaked protagonist along with location work with stars Romy Schneider and Serge Reggiani – does, indeed, look amazing. But what Bromberg’s film also makes clear is Clouzot’s notoriously obsessive perfectionism combined with a free reign to do whatever he wanted resulted in the filmmaker estranging his cast and crew (a number of whom walked off the set never to return) and driving himself to distraction and finally ill-health.

“A filmmaker couldn’t have been more acclaimed and more famous than Clouzot,” Bromberg says. “He was one of the great masters of cinema, and in 1964 Clouzot was at the peak of his career. Even so, when the film started he didn’t have the unlimited budget some people say he had.

“However, Columbia Pictures wanted to be big in Europe and in 1963 they had given another director an unlimited budget, Stanley Kubrick for Dr Strangelove, which was a huge success. So in 1964 the film’s American producers stopped in Paris on the way back from Japan and they watched the screen tests Clouzot had done for L’enfer, were impressed by what they saw and decided to try the unlimited budget again.

“The problem was,” Serge says, “Clouzot had been in the business a lot longer than Kubrick and when he was told he could have as much of everything as he wanted, his response was: ‘OK, I want it all’. And Clouzot placed great expectations upon himself, so when he was given that financial freedom he started working and did not stop.”

Until, that is, a heart attack stopped him in his tracks. The troubled production closed down, Clouzot went into a period of convalescence and creative inactivity and the footage he had in the can stayed there for the next 35 years. L’enfer was eventually filmed by Clouzot’s protégé Claude Chabrol in 1994, but Chabrol’s version of Clouzot’s script has none of his mentor’s experimentation and, of course, does not bear the auteur’s signature.

We’ll never know for sure whether Clouzot’s L’enfer would have been any good, but Bromberg’s film gives us an idea of what it might have been like. And the story of the making of L’enfer is utterly compelling, while the unmaking of its maker (an awful mirror to the fate of the film’s protagonist) is an engrossing example of, for want of a better term, the hell of being a tormented artistic genius.

“I have always thought that Clouzot was a master,” says Bromberg, “but in making this film I realised he was also a man who had his doubts and his failures. I like to think a genius is a person who overcomes doubts to make something great. I think if Clouzot hadn’t had that heart attack, he would have found a way to finish L’enfer.

“That doesn’t diminish Clouzot,” adds Bromberg. “On the contrary, it makes him bigger.”

Henri-George Clouzot’s Inferno is at Glasgow Film Theatre from Saturday.