The sad news was confirmed by her son, musician Thomas Dutronc, who shared a simple message on social media.
Alongside a touching photo of himself as a baby with his mother, he wrote, ‘Maman est partie’ alongside many heart emojis, which translates to ‘Mom is gone.’
Hardy, known the world over for her crystalline voice and melancholy lyrics, suffered with different types of the disease, including lymphoma and laryngeal, over two decades.
It made her a passionate advocate for euthanasia, as she declared her home nation 'inhuman' for not allowing the procedure.
Her son Thomas Dutronc, whose father is fellow singer Jacques Dutronc, announced her death in a simple post to Instagram tonight which read: 'Mum is gone.'
Hardy rose to prominence at just 18 with her first hit 'Tous les Garcons et les Filles' ('All the Boys and Girls') in 1962, and helped found the ye-ye style of music, a pop-inspired cultural movement that embraced British and American rock in the 1960s.
Her status as a cultural juggernaut saw her schmooze with the biggest names in showbusiness at the time, rubbing shoulders with the likes of Mick Jagger and Bob Dylan.
She also worked with songwriters including Serge Gainsbourg, Patrick Modiano, Michel Berger and Catherine Lara.
