France, 1950s. From the Quartier Latin to Saint-Tropez via New York, a young Parisienne becomes the icon of a whole generation. In 1954, 19-year-old Francoise Sagan shot to fame with her first novel, Bonjour Tristesse. Flamboyant, scandalous and underrated, Sagan lived her life at the furthest edge of excess. She won and lost fortunes at the roulette table, bought and crashed superb sports cars, drank, danced and partied, leaving a trail of lovers in her wake.

Julien and his mum care for each other very much. But Julien has committed a deadly sin: he is growing into a teenager! Worse, he has found himself a girlfriend of his age. "Mummy" is not going to tolerate such an ignominy. Julien is HER baby and will remain HERS for ever, encouraged in her "crusade" by her bovine husband and barely thwarted by the more courageous interventions of Suzanne, Julien's sympathetic big sister.