suggestions for towns near Switzerland

My husband and I are planning to return to Switzerland this fall, and would like to extend our trip by adding a few towns reachable by train from Switzerland. We are looking for pretty, walkable towns or small cities with a historic center, and good food. Thinking of France, Italy, or Germany. Hotel and restaurant recommendations and travel tips gratefully accepted. If you have a favorite location that is available by plane, we would consider that too. Thank you for taking the time to read and respond to my post.