I know of this place in our neck of the woods in Bex (VD) near lake Geneva (about 12mins by train from Montreux or 30 mins from Lausanne) - trains run to and from Bex every hour in both directions and you could easily pick up and drop off by train. The shop is walking distance from the station (about 7 mins). French for renting is "location". You could also try searching yellow pages or google under "location velo"
http://www.newbike.ch/page%20location/location.htm