If I buy a multi-site pass, do I have to visit all the sites on the same day ?

No. When booking, you must choose a date for each site. Please note that Lascaux IV and the Parc du Thot are 7km apart by car, and the Laugerie-Basse and Grand Roc sites take 35 minutes to reach Les Eyzies. You must choose a time and date for the guided visits to Lascaux IV and Grand Roc. Le Thot and Laugerie Basse can be visited at your convenience.