The calculated distance (air line) between Saint-Gély-du-Fesc and Marseille is approximately 84 miles respectively 134 kilometers.
By car or train, the actual journey to Marseille is certainly longer, as only the direct route (as the crow flies) between Saint-Gély-du-Fesc and Marseille has been calculated here.
Air line (approximately)
134 kilometers
73 nautical miles