Correction: An earlier version of this obituary misspelled the last name of actor Eiji Okada. The article has been corrected.

FILE - In this May 21, 2012 file photo, director Alain Resnais listens during a press conference for You Havent Seen Anything Yet at the 65th international film festival, in Cannes, southern France. Seminal filmmaker Alain Resnais, whose inventiveness in film made him among the world's cinema greats, has died Saturday March 1, 2014. He was 91. (AP Photo/Joel Ryan, File) (Joel Ryan/AP)

Alain Resnais, a French filmmaker who directed a riveting early documentary about Nazi concentration camps and whose later films “Hiroshima Mon Amour” and “Last Year at Marienbad” melded opulent, baroque imagery with complicated narratives that could be as puzzling as they were compelling, died March 1 in Paris. He was 91.

Producer Jean-Louis Livi confirmed that Mr. Resnais had died but did not provide a cause of death.

Mr. Resnais, a major figure in international cinema in the 1950s and ’60s, was occasionally linked to the “new wave” of unconventional French filmmakers, including François Truffaut and Jean-Luc Godard.

The new wave is often associated with films that were lyrical, fast-paced, easy to watch and imbued with a cheeky youthfulness. Mr. Resnais developed a different path. As Richard Roud, a co-founder and the first director of the New York Film Festival, put it, a Resnais film was always a “calculated work of art. It is not spontaneous, it is not realistic and it is complex.”

This was true of much of Mr. Resnais’s later work but not of the short documentary with which he established his reputation. Made just a decade after World War II ended, “Nuit et Brouillard” (“Night and Fog”) (1955) is often credited as the first filmic evocation of the Nazi concentration camps, including Auschwitz.

A mixture of grisly black-and-white photographs taken during World War II combined with quiet color images of the now-empty camps, the 30-minute film could not be more straightforward and harrowing. Writing in the New York Times in 2000, film critic Stuart Klawans said “Night and Fog” “remains an unsurpassed meditation on the Holocaust.”

The text was written and narrated by the poet and publisher Jean Cayrol, a survivor of the Gusen camp in Austria.

“If one does not forget, one can neither live nor function,” Mr. Resnais told an interviewer in 1966. “The problem arose for me when I was making ‘Nuit et Brouillard.’ It was not a question of making yet another war memorial, but of thinking of the present and the future. Forgetting ought to be constructive.”

His emphasis on memory — more as an intellectual or even elliptical exercise than as straightforward dramatic narrative — pervaded much of his subsequent work.

With “Hiroshima Mon Amour” (1959), Mr. Resnais initially envisioned a documentary similar to “Night and Fog,” but he altered his vision after consulting with the French novelist Marguerite Duras.

She turned in a script with 16 pages of dialogue, a spareness that allowed the director to shape a stylized narrative centered on the tortured affair between a French actress (Emmanuelle Riva) and a Japanese architect (Eiji Okada).

The result, which Time magazine called “an intense, original and ambitious piece of cinema,” combined documentary footage with a love story told in present tense but forever overshadowed by the memory of atomic catastrophe and her earlier love for a German soldier who was killed during the Allied liberation of France.

As he did with “Hiroshima Mon Amour,” Mr. Resnais often worked with writers who were not yet generally associated with the film world. His next major project was “Last Year at Marienbad” (1961), a collaboration with the French avant-garde novelist Alain Robbe-Grillet.

“Last Year at Marienbad,” featuring Delphine Seyrig, Giorgio Albertazzi and Sacha Pitoëff, focused on a man’s attempts to persuade a woman that they had an affair a year earlier. The surreal film regularly turns up on lists of the “best” and the “worst” movies ever made.

By design, the characters — known only as A, X and M — have no more humanity than figures on a chessboard, variables in an equation or dummies in a store window. For that reason, it has often been said that half of the fashion photography of the past 50 years owes a debt to “Marienbad.”

The movie represented an effort to “determine if it is possible to represent, even roughly, the mechanics of thought, not in reality, but in the minds of the characters,” Mr. Resnais told a reporter at the time.

Attempts to discern a plot, discover a hidden message or make an emotional connection with the characters in “Marienbad” are doomed to failure. “Marienbad” is best followed as if it were a string quartet, a ballet or a mysteriously animated painting that changes ever so slightly as you watch.

“With ‘Marienbad,’ Resnais carried the cinema farther than it has ever gone before without worrying about whether or not audiences would follow,” Godard told the New York Times in 1962. “If he were a novelist or a poet, this wouldn’t matter — but in the cinema, you’re supposed to worry about your audience. Alain knows this and that’s why he seems so contradictory and mysterious. He’s trying to hide his obsession with his art.”

Alain Resnais was born on June 3, 1922, in Vannes, an ancient village in Brittany where his father ran a pharmacy. A fragile child, Mr. Resnais was educated mostly at home. On his 12th birthday, he was given an 8mm camera and began to make home movies, with his friends given starring roles.

His fascination with the visual arts dated to childhood, when Mr. Resnais had been a devoted reader of comic strips. He suggested that his interest in flashbacks and what he would dub “flashforwards” might have been inspired by his love of Milton Caniff’s long-running cartoon “Terry and the Pirates.”

“It was an impossible task to find that story in France because it would be published for two weeks and then disappear,” he told film scholar James Monaco. “Then I would find it in Italian and then that would disappear, too. And after that there was a war and so I had to read ‘Terry and the Pirates’ in complete discontinuity.

“Well,” he said, “I discovered that it gave the story a lot of emotion to know Terry when he was 14 and then when he was, say, 24, after which I would make up myself what had happened to him when he was 22 or 17.”

At 17, Mr. Resnais moved to Paris and studied acting before entering the French military toward the end of World War II.

Afterward, he began making short movies about artists such as Paul Gauguin and Vincent van Gogh, the second of which won an Academy Award for best short film. He also directed a film about the Nazi bombing of the Basque city of Guernica and Pablo Picasso’s artistic response to it.

“Providence,” made in 1977, was Mr. Resnais’s first film in English. Despite a cast that included John Gielgud as a dying English novelist, it was savaged by most critics. The New Yorker film reviewer Pauline Kael was particularly hard on Mr. Resnais, reducing his technique to “beautiful diddles.”

“Providence” eventually found passionate admirers. And Monaco, in a riposte to Kael, believed he had found the key to Mr. Resnais’s work.

“Alain Resnais’ films, far from being the complicated and tortuous intellectual puzzles they are reputed to be, are rather simple, elegant, easily understood — and felt — investigations of the pervasive process of imagination,” he once wrote. “It doesn’t even take much imagination to enjoy them. All that is necessary is an understanding that we are watching not stories but the telling of stories.”

Among Mr. Resnais’s other most-celebrated films are “La Guerre Est Finie” (“The War Is Over”) (1966), a drama starring Yves Montand as an aging Communist Party revolutionary in Franco’s Spain, and “Stavisky” (1974), with an instrumental score by Stephen Sondheim.

Mr. Resnais’s works included “Muriel” (1963), a melancholy rumination on the Algerian war; “La Vie Est un Roman” (1983), an interweaving of three disparate tales spread across several centuries; “I Want to Go Home” (1989), an excursion into the world of comic books that was set in Cleveland to a script by cartoonist Jules Feiffer; and three settings of plays by the British author Alan Ayckbourn, including “Smoking/No Smoking” (1993).

Florence Malraux, the daughter of the French author and politician Andre Malraux, was an assistant director for most of Mr. Resnais’s films after and including “Marienbad.” They were married in 1969 and later divorced. His second wife was the actress Sabine Azéma, who appeared in many of his films from the early 1980s and whom he married in 1998.

A complete list of survivors could not be immediately confirmed.

The tall, formal, soft-spoken Mr. Resnais was generally liked personally by those he met, including critics who didn’t always admire his work.

“I make difficult films,” Mr. Resnais acknowledged in 1962, “but not on purpose.”