Hi, within the Parc du Mercantour the forest roads are prohibited for motor vehicles (excluding farmers who have a special permit) and bicycles. They are free on foot. There are some exceptions, the Piste de la Dea is authorized for bicycles. Source:
https://www.mercantour-parcnational.fr/sites/mercantour-parcnational.fr/files/consultations/cartes-vtt.pdf
So this road is free for everyone to walk and cycle, but requires a motor vehicle permit. Did I indicate the tags correctly?