The GR® DE PAYS TOUR DES DENTELLES DE MONTMIRAIL is a well know 60 km loop in the Ventoux region of France.
Many web sites detail the itineray including all it features which include beautiful castles and villages such as Vaison la Romaine or Le Barroux, the beautiful vineyards of Beaumes la Venise, and then of course wonderful views of the Dentelles rocks and of the Ventoux mountain. The trail mixes up techical single track, with tractor tracks and some faster sections on very quiet roads.
As a walk this is typically recommended for between 3 and 6 days. The GR guide is included in the link below.
Randonnée Tour des Dentelles de Montmirail - GR® de Pays - 3 à 6 jours (provenceguide.com)