The calculated distance (air line) between Roquebrune-Cap-Martin and Nîmes is approximately 156 miles respectively 251 kilometers.
By car or train, the actual journey to Nîmes is certainly longer, as only the direct route (as the crow flies) between Roquebrune-Cap-Martin and Nîmes has been calculated here.
Air line (approximately)
251 kilometers
135 nautical miles