Parkinson's disease (PD) is a neurological condition, which affects the brain. PD gets worse over time, but how quickly it progresses varies a lot from person to person. Some symptoms of PD are tremors, stiffness, and slowness of movement. This study will assess how effective foscarbidopa/ foslevodopa is in treating French adult participants with advanced Parkinson disease under routine clinical practice. Foslevodopa/foscarbidopa is an approved drug outside of US for the treatment of Parkinson's Disease. Approximately 200 adult participants who are prescribed foslevodopa/foscarbidopa by their doctors will be enrolled across approximately 30 sites in France. Participants will receive foscarbidopa/ foslevodopa subcutaneous infusion as prescribed by their physician. Participants will be followed for up to 12 months. There is expected to be no additional burden for participants in this trial. Participants will attend regular visits during the study at a hospital or clinic according to their routine clinical practice.