Sarah's Key is a story about a young Jewish girl, her brother and the French Police in Paris, July 1942. It intertwines with a journalist - 60 years later and some clues she discovered about these 2 young children. It is a fictional story about the great Velodrome d'Hiver roundup - July 16, 1942, in the heart of Paris.
It is the author's tribute to the children of the Vel' d'Hiv'. The only true part of this story is the roundup.
A very good read, as far as I am concerned. Buy or borrow it to read.