France has an excellent cycling trail network and facilities. In regions that have popular bike trails there are usually small localized companies that allow you to do one way bike rentals.
Freewheelingfrance is a website that contains a list of rental agencies and tips around cycling in France.
The Alsace, the region asked about in the question is very popular for it's wine and vineyard cycling trail. So there will be plenty of bike hire places in the area. I don't know about the specific locations asked about, but I would expect many agencies will offer one way rentals along the route. As with hire cars, one way rentals usually incur an additional fee.