After a year at the Sorbonne, she answered a newspaper advertisement looking for young singers. Hardy signed her first contract with the record label Vogue in November 1961. In April 1962, shortly after she left university, her first record, "Oh Oh Chéri", appeared, written by Johnny Hallyday's writing duo. Her own flip side of the record, "Tous les garçons et les filles", became a success, riding the wave of yé-yé music in France. It sold over a million copies and was awarded a gold record. The track peaked at No. 36 in the UK Singles Chart in 1964. She reportedly hated the song, saying that it was recorded "in three hours with the worst four musicians in Paris". She was dating photographer Jean-Marie Périer at this time, and his shots are featured on many of her record sleeves.