The calculated distance (air line) between Saint-Genis-Laval and Montpellier is approximately 151 miles respectively 243 kilometers.
By car or train, the actual journey to Montpellier is certainly longer, as only the direct route (as the crow flies) between Saint-Genis-Laval and Montpellier has been calculated here.
Air line (approximately)
243 kilometers
131 nautical miles