While I have not read the novel by Marguerite Duras I count Peter Brook's Moderato cantabile to the film adaptations which convey a true Duras flavour.
Monsieur Desbarèdes is the biggest boss of the little ocean seaport town, the CEO of the great foundries. The family lives in the most lavish mansion at the end of la Boulevard de la Mer. The little town is located in Gironde, Aquitania, by the Atlantic Ocean. "There is always a wind here". Every day Anne Desbarèdes takes her little son to a piano lesson at a strict music teacher, Mlle Girard, to practice sonatinas by Diabelli, who composed an entire cycle of them for children. One day there is a shattering scream from the bar de La Gironde downstairs. The piano lesson is interrupted, and Anne joins the crowd shocked to see the female murder victim. There is a chance meeting with a young, handsome, unemployed witness, an ex-worker at the Desbarèdes foundry, called Chauvin. Anne and Chauvin start to meet daily to figure out theories about the murder case. A Platonic love affair begins. At home Anne is alienated as the hostess of high society soirées, and her stern husband is upset by her visible estrangement. At the end there is another shattering scream at the bar, by Anne, after Chauvin has left her forever.
Central motifs include - the sea - the clouds - the fog - the wind - screaming birds - boats and ships - cranes - harbour equipment - sirens - the Diabelli sonatina - red wine (consumed by Anne often) - the wood, the bare springtime trees - and magnolias (Anne's signature flower).
It is a facade marriage, but also the relationship of Anne and Chauvin is Platonic. The sole real love affair is between Anne and her son.
Peter Brook, still active, is one of the greatest theatre directors since the 1940s, but he has also a distinguished career as a film and tv director.
The mise-en-scène of Moderato cantabile, largely shot on location, is very cinematic, and the black and white CinemaScope frame is constantly dynamic.
The little son Pierre has talent in music, but little motivation. He has no patience with "moderato cantabile". He wants to go out to play with other children.
Anne is stuck in a loveless facade marriage, but she has no energy to change things. She is drawn to Chauvin, but although she is the active partner, she does not take the decisive step to a love affair. She does not really want to play.
It's a study in frustration, melancholia, solitude, and alcoholism. Anne is drinking too much. She neglects blatantly her duties at the final high society soirée, makes a fool of everybody, and embarrasses her husband utterly. At the bar, Chauvin abandons her, she emits a piercing scream, and faces the glaring light of her husband's automobile.
The film has been strikingly shot by Armand Thirard, and the brilliant 35 mm print does justice to the photochemical glory of the cinematography.