The calculated distance (air line) between La Grande-Motte and Aix-en-Provence is approximately 68 miles respectively 110 kilometers.
By car or train, the actual journey to Aix-en-Provence is certainly longer, as only the direct route (as the crow flies) between La Grande-Motte and Aix-en-Provence has been calculated here.
Air line (approximately)
110 kilometers
59 nautical miles