Сайн уу гуниг минь by Françoise Sagan - Goodreads
17-year-old Cécile spends her summer in a villa on the French Riviera with her father Raymond and his current mistress, the young, superficial, fashionable Elsa, who gets on well with Cécile. Bonjour Tristesse is a novel by Françoise Sagan. Published in 1954, when the author was only 18, it was an overnight sensation.