The film, directed by British film-maker Saul Dibb and starring Michelle Williams and Kristin Scott Thomas, is, according to Williams, "entirely dedicated and a tribute to Irene Nemirovsky and her descendants," a Jewish author from the Ukraine who settled in Paris.
Despite her conversion to Roman Catholicism, she was arrested by the Nazis and died, aged 39, at Auschwitz concentration camp in 1942.
"It's quite overwhelming, the level of emotion you feel when you even think about Irene's story as it's more extraordinary than anything she wrote, even Suite Francaise," says the actress.
"As soon as I read the script, I could see Irene, and hear her voice around me. It very rarely happens, but her words sounded like music to me."
Williams, the winner of a Golden Globe in 2012 for playing Marilyn Monroe in Simon Curtis's  My Week With Marilyn, adds that "when you are dealing with the legacy of a real life person, it's a responsibility heaped on you.
"You want to be true to that person, and in this case, I wanted to be faithful to Irene. The fact that this story was very nearly never published makes it more precious."
Williams plays the role of Lucille, a young wife in the French provincial town of Bussy, who waits for news of her husband, fighting for France, under the disapproving eye of her mother-in-law, played by Kristin Scott Thomas.
She meets a young German officer and falls in love, even as the town is brutalised under occupation from its invaders.
In the novel, Lucille's love affair is just one of many stories Nemirovsky weaves of life under Nazi control. But Suite Francaise, written in tiny handwriting in a notebook as paper became more scarce, was never completed.
Nemirovsky was taken to Auschwitz, and her notebook was passed to her youngest daughter, Denise Epstein, who didn't open it until 2004, thinking it contained her mother's journals.
Upon discovery and publication, Nemirovsky was posthumously awarded the prestigious French literary prize, the Prix Renaudot, and her other novels were also successfully republished.
Expressing her sorrow that Epstein died in 2013, "just before we made the film, and so I never got to meet her," Williams calls meeting the author's descendants "the most special day of filming; they came to the set, and it was emotional for everyone".
And Scott Thomas added: "It just really is all about the incredible story of Irene and her book, and I just hope the film has done it justice, because its publication was very important - it's a historical document for France.
"This tale of violent occupiers - this is recent history we are re-telling, from the time of our grandparents, and it has terrible poignancy for today as well, all over the world.
"I think what was interesting is that Irene had no Jewish characters in her book, or anything to say about their persecution.
"Some commentators have called her anti-Jewish as she hadn't embraced or exposed what was going on with her people at that period in France.
"However, in our film version, we have a moment where you do see what is happening to the Jewish people, and that was our own tribute to the fate of Irene."
Director Dibb, whose previous work includes The Duchess, starring Keira Knightley, describes adding those scenes as "a necessary piece of artistic licence".
"Irene wrote so generously about her occupiers. The book was written in 1940, in the early stages of the war, and she doesn't even refer to them as Nazis.
"She had no perspective on what happened to her people, and what happened to France. However, she was killed by her occupiers, and killed by those French collaborators too, who helped deport their Jewish populations."
Williams defends the choosing of just one storyline from the original novel, saying, "the book itself is incomplete and so fragmented that it would be difficult to tell as a film unless one story is picked out.
"I'm glad they chose Lucille's love story - I think many people will identify with the story of love in hopeless circumstances.
"But what's also interesting for me is my character starts out as fragile and naïve, and becomes a revolutionary. The circumstances we live in dictate who we become.
"I'm just sorry that I never got to see or hold the original manuscript of the book, and actually see Irene's writing, although I do have a first edition of the book. But I hope we have also helped her to live on."
Suite Francaise is released in the UK on 13 March.
It's a book that lay undiscovered for 60 years and which went on to become a phenomenon: Irene Nemirovksy's epic French novel Suite Francaise, written in the early years of the World War II, not only became a worldwide bestseller upon its publication in 2004, but is now an English language movie.