Swizterland is where Fanny went on her honey-moon as stated in the text, "As for the bride, she was subdued and tearful, as an orthodox bride should be; and invited all her sisters in turn to come and stay with her at Notting Hill directly the honeymoon in Switzerland should be over." (Ch.16). Within the late 19th century, Switzerland entered a period of industrialization and the country's banking along with its' tourism industries started to boom. Switzerland was one of Europe's richest nations, so it would seem ideal for a honeymoon trip for Fanny and her husband. 

This is the part of France where La Vallee is located, where the novel begins and where Emily has been raised in her youth.

Fun fact: The old city (before the new one was constructed on top of it) used to be called the "Sleeping Beauty" because pollution had turned the city's walls black (https://www.udrive.com.au/blog/fun-facts-about-french-city-bordeaux/).