Sarah's Key by Tatiana De Rosnay

ahhhhh....
Skipped Norwegian Wood and Glimmer....
And started Sarah's Key by Tatiana De Rosnay

It's a novel but the plot's based on true incidents happening around 1942 with Jewish families in France being deported to Auschwitz.
Happening along with this story is an American-writer who was married to France. Her editor asked her to cover the 60th anniversary of the Vél' d'Hiv' roundups, leading her to find out about Sarah, who in 1942 was one of those who got deported and her family killed in the Nazi camp.