The calculated distance (air line) between Saint-Maximin-la-Sainte-Baume and Cassis is approximately 23 miles respectively 37 kilometers.
By car or train, the actual journey to Cassis is certainly longer, as only the direct route (as the crow flies) between Saint-Maximin-la-Sainte-Baume and Cassis has been calculated here.
Air line (approximately)
37 kilometers
20 nautical miles