We are not serious when we are 18 years old. Françoise Quoirez has just missed her first year of university. She will not make her license of letters. Françoise is bored, in the summer house, in Hossegor, far from the bistros of Saint Germain-des-Prés.

Francoise begged her father, a severe and tender industrialist, to bring her back to Paris: "I will make you some dishes." She is the favorite of her three children. He smiles. Here they are in the great apartment on the right bank, as sad as a funeral. Françoise is very talented to turn cookery in Beirut under bombs. This will be the restaurant, suggests Dad. Paris in August fout the cockroach. "L'Epicerie", his night club, is closed. The "buddies" have spun by the national 7. Objective Saint-Tropez, new Babylon of the revelers who abolished the day and the night. Diving. Bronzer. Dance. Like. To drink. Everything is confused in this bacchanal of insomniac enjoyers. Francoise wanders through the gray city heated by a dusty sun. One morning she climbed the Arc de Triomphe. An image arises: that of a woman met in Cannes. "The great lady" with mysterious customs. Françoise runs away in her room in the Boulevard Malesherbes, draws the curtains and slaps the most famous novel of the post-war period in seven weeks. A crusader in love with the tragic end. Paul Eluard gives him a beautiful title: «Bonjour tristesse». Marcel Proust, a beautiful pseudonym: Sagan.

She wonders if it's worth a nail. Sends it to two publishers. Julliard is the fastest. Unzips his checkbook and writes a number to several zeros. "Usually I draw a first novel at 3,000, but for you it will be 4,200 copies. A few months later, the publisher sold a million. The universal glory. The escapades. The legend, perhaps greater than the work.

These days, Julliard reprints eight of his novels and "Hello Sadness" in a version identical to the original one. A little sun in the warm water of the re-entry. See you Francoise, "the charming little monster" that we miss so much.

"Hello sadness", ed. Julliard, 17 €.