Born into the wealthy Camondo family of Paris, she was the daughter of Count Moïse de Camondo and Irène Cahen d'Anvers, both of whom were from prominent Jewish banking families. One of two children, her older brother Nissim served as a fighter pilot during World War I and was killed in action in 1917.
- Fanny (born 26 July 1920 in Paris, died in 1943 at Auschwitz)
- Bertrand (born 1 July 1923 in Paris, died in 1943 at Auschwitz)
On her father's death in 1935, Béatrice inherited a large fortune. Her father bequeathed his Parisian home, including its contents and a major collection of art, to the Musée des Arts Décoratifs to be used to create the Musée Nissim de Camondo in his son's honor.
A convert to Catholicism, Béatrice felt safe in Paris after the Nazi occupation. Divorced from her Jewish husband Léon Reinach, she believed that her wealth and the influential people she rode horses with in the Parc Monceau would shield her from being taken. In the Musée Nissim de Camondo, on the top floor, there is a letter from her ex-husband telling Béatrice to leave Paris with their son and daughter. However, she disregarded his advice.
In 1943, under the German occupation of France during World War II, Béatrice, her ex-husband and their two children were forcibly removed from Paris and taken to the Drancy deportation camp north of the city. From there, they were subsequently deported to Auschwitz concentration camp, where they all died. Ironically her Aunt Elisabeth Cahen d'Anvers(1874–1944) who had also divorced and converted to Catholicism was also imprisoned at Drancy deportation camp and died at KZ Auschwitz.
- Steinbach, Alice (August 15, 2004). "Past, Prologue and Paris". The New York Times.
- Michlin, Gilbert (2004). Of no Interest to the Nation: A Jewish Family in France, 1925–1945. Wayne State University Press. p. 122. ISBN 978-0-8143-3227-6.
- Birnbaum, Pierre (1996). Les Fous de la République. Stanford University Press. p. 9. ISBN 978-0-8047-2633-7.