The New York Times review got it right:
To describe “A Secret” as a Holocaust movie would be perfectly accurate but also somewhat misleading. Its chronology is complex and elusive. It shifts from the immediate postwar years into the 1980s...and then back into the anxiety and panic of impending and actual war. In those days Maxime spelled his last name Grinberg, he was married to a woman named Hannah (Ludivine Sagnier) and the two of them occupied the stolid center of a large and complicated extended Jewish family.There is so much more to say about this movie, and given my past studies in 20th century French history, I feel compelled to say it. But I also want to wait until I have the chance to discuss it with one of my mentors and friends to get his take (and to ask him if he agrees with me about one possible anachronism amid all the incredibly good historical detail).
That family, as it heads toward catastrophe, is as much the setting of the story as its subject, and their fate as Jews under Nazi occupation is entangled in murky, sticky domestic issues of jealousy, betrayal and desire. An erotic spark ignites the first time Maxime and Tania meet — the day of his wedding to Hannah — and it causes plenty of guilt and tension. But it might have been safely (if agonizingly) extinguished in more peaceful times....
What is most impressive about “A Secret” is the way Mr. Miller artfully and gently gestures toward such enormous themes without spelling them out. Nearly every melodramatic impulse has been suppressed in favor of a calm precision that serves both to intensify and delay the emotional impact of the film’s climactic disclosures.
The film is just becoming known here in the United States, where Grimbert will be meeting with American readers/audiences in the coming days. I've already ordered the original novel from amazon.fr (it has been published in English in the United States as Memory), and I'm looking forward to hearing what the author of this intense, and intensely sad, story has to say when I attend this event at the Mercantile Library Center for Fiction in Manhattan. Keep an eye out for any Grimbert appearances near you. And go see that movie. ASAP.