Another primary theme found throughout Tatiana de Rosnay's novel Sarah's Key is that horrific circumstances reveal both the best and worst of human nature. As mentioned above, this is a story set in Paris in 1942, a time of deportation and extermination for Jews. The name of the architect of the Holocaust, Adolph Hitler, is only mentioned once. None of the now infamous Nazi leaders appear anywhere in this novel. This is the story about how ordinary people deal with extraordinary circumstances.
The people who gather, transport, and guard the Jews are common people. Those who see what is happening fall into two categories from bothends of the spectrum: those who try to help and those who try to hurt in order to save themselves. The selfish and the self-less. The concierge in Sarah's building gleefully turns the Starzynskis in to the police--even though Sarah's mother used to babysit for her child--and will profit from doing so. The doctor who comes to the Dufaures to treat Rachel leaves the unassuming, peaceful home and immediately turns the family in to the authorities. Rather than being concerned about his patients, the doctor clearly wants to help his own cause by abetting the Germans.
In contrast, a few people took risks to try to help the Jews in their horrible position. Some women try to get food to the obviously starving children; the officer takes pity on Sarah and Rachel and allows them to leave--and gives them money to help them on their journey. (That money does, eventually, save Sarah from being put back in prison.)
The theme is clear: even in dire circumstances, people get to choose how they will respond. The families at every other farmhouse where Sarah and Rachel stopped for help turned the girls deliberately away; however, the Dufaures were willing to risk their own lives to help these sick and starving girls. Everyone saw the same injustice and inhumane treatment happening; only a few chose to do something to help. This is, unfortunately, a consistent pattern in human nature.
As Julia Jarmond (a modern reporter) seeks to write an article for the 60th anniversary of the Vel d'Hiv', she discovers her own family by marriage is directly involved in one survivor's life through an apartment which was abandoned during the time of the roundup.
As historical fiction and a Holocaust account, one of the main theme's of this book is the remembrance of this horrific event and an honoring of the lives that were both lost and those that survived. The roundup of Jews from Paris, France, (most of which were young children and French citizens), imprisonment in the Velodrome, and shipment to death camps such as Auschwitz, is a moment in history that even France was reluctant to acknowledge until very recently.
Tatiana de Rosnay weaves two parallel stories in this novel in order to show how one marked event in the past has continued to cause pain and heartache to many in the future. Certainly there is an element of mystery and suspense as the details of Sarah's life unfolds for Julia, but in the end, the main message is one that takes guilt and regret, exposes the truth and provides emotional closure.