NEW YORK – The Metropolitan Opera’s Dialogues des Carmélites production has been in repertoire since 1977 – nearly as long as music director Yannick Nézet-Séguin has been alive. But it’s so beloved that of course he claimed it for his inaugural season, working the opera into his schedule just prior to taking the Philadelphia Orchestra to China.

The Friday opening – one of only three performances, the final one, on May 11, an HD simulcast in movie theaters around the world – hadn’t entirely gelled, but all of the right things were there. And that includes a starry, carefully picked assemblage of singers, more detailed stage direction than any revival that I can remember, and Nézet-Séguin’s original approach toward the orchestration that not everybody will like but that may signify a new chapter in the opera’s performance history.

This one-of-a-kind opera needs the all-hands-on-deck treatment that it receives here: The story about Carmelite nuns executed during the French Revolution’s Reign of Terror feels all the more powerful for the John Dexter production’s austere power of suggestion. You hear the guillotine, for example, but never see it. The music itself has none of the usual crowd-pleasing elements, such as catchy tunes, soaring love duets, or swift-moving narrative. Instead, this 1957 opera behaves more like a novel, gaining its power from an accumulation of character-based details, often amid washes of sound that allow much dramatic, vocal, and orchestral leeway.

Some conductors convey beatific warmth; Nézet-Séguin’s more Expressionistic approach echoed Poulenc’s influences from the emotionally detached medieval sacred music, while also projecting great inner turmoil behind the exterior simplicity of Carmelite life. The performance had a strong sense of pulse – tempos for this opera are said to have quickened since the composer’s 1963 death – and orchestral details that made you question what you thought you knew about the opera. Sensuous harp writing felt strange in close proximity to contemplation of the Blessed Virgin Mary. The knife’s-edge brass writing was more prominent, reminding you that no cloister is truly safe.

For some listeners, it may be like seeing the Sistine Chapel frescos after being cleaned – unsettling, and in this case, a bit unsettled considering that the orchestra’s loudness drowned out some singers during Act I. Still, revival director David Kneuss underscored the opera’s depth of characterization – and the problem of a stage full of nuns in barely differentiated costumes – with a body language that spoke to their inner conviction (in contrast to the external bluster of our modern life), but each with their own, individual physicality while facing adversity. My favorite was an elderly nun who first walks with a cane and suddenly decides she doesn’t need it.

Vocally, opera-goers often have a long list of cherished Carmelite casts, from Lucine Amara to Regine Crespin to Jessye Norman to Teresa Stratas. It’s too early to truly evaluate the current cast. In a role debut, Karita Mattila was most eagerly anticipated in the short but pungent role of the old prioress, who has one of the longest and most bitter death scenes in all of opera. Mattila’s acting was intense, but she’s still finding her way into the lower-lying vocal lines.

Statuesque Isabel Leonard is not the most obvious choice for the central role of sheltered, frightened Blanche, who seeks refuge in Carmelite life. Incapable of being mousy, Leonard was convincingly distracted and withdrawn, and rightly saved her richest singing for last. Top vocal honors, at this point, go to Adrianne Pieczonka as the new prioress, who showed how much clean vocal precision is rewarded in Poulenc’s music. Other singers, including Karen Cargill as Mother Marie, veered toward a more Puccinian manner, which also works (the opera premiered at La Scala). More will be revealed at the May 11 simulcast.

OPERA REVIEW

Further performances are May 8 and 11 at the Metropolitan Opera in New York City. Tickets: $154-$495. The May 11 simulcast will be seen in eight Philadelphia-area theaters. Information: 212-362-6000 or www.metopera.org.