As the yé-yé era drew to a close in the late 1960s, Hardy sought to reinvent herself, casting off the fashionable, girl-next-door image that Périer had created for her and abandoning the "cute" and catchy compositions that had characterized her repertoire up to that point. She began working with more accomplished songwriters such as Serge Gainsbourg and Patrick Modiano. Her 1971 album "La question" represented an important turning point in her career, moving towards a more mature style; it remains her most acclaimed work and has generated a dedicated cult following over the years. The early 1970s also marked the beginning of Hardy's renowned involvement with astrology, becoming an expert and writer on the subject over the years.