Singer Celine Dion performed at the opening ceremony of the 2024 Paris Olympics on Friday, marking her first live performance since her Stiff Person Syndrome diagnosis. She sang Hymne A L'Amour by Edith Piaf. Stiff Person Syndrome is a rare and progressive neurological disorder, symptoms of which include painful muscular stiffness. The 56-year-old revealed her diagnosis in December 2022.