Some other notable film roles include Elsa in Otto Preminger's Bonjour Tristesse (1958), alongside Deborah Kerr and David Niven, and as Milady de Winter in Les Trois Mousquetaires (1961).

[21] At the time of her death, she was starring in Thomas Gilou's film Maison de retraite (2022) alongside Gérard Depardieu, one of the biggest box office hits of 2022 in France.

Her parents, both actors themselves, had met in Shanghai, China,[26] where her half-brother, Léonid Ivantov, from the first marriage of her mother, was born, in Harbin on 17 December 1923.

[27] Like hundreds of other major European figures of stage and screen, she trained at the Cours Simon in Paris where her classmates included Jean-Pierre Cassel, Claude Berri and Guy Bedos.

[32] Demongeot was the victim of a financial scam set up by her account manager who stole €2 million from her, money which was used to make loans to numerous high-profile personalities, like Isabelle Adjani, Alexandre Arcady or Samy Naceri.