@futurefjp , the Swiss Friends of St James have a file with contact details. It's in French, but pretty easy to understand. The file covers Fribourg ( my home state in Switzerland) to Geneva, so you only need the last two pages.
The important columns in your case, are the ones with the heading Catégorie, and Prix (price).
In the Catégorie column, look for ACUE, which Stands for accueil jacquaire. This is a private home, owned by a member of the Friends of St James, willing to provide accommodation on a donativo basis. The column Prix is then going to read: Contribution libre, which means donativo.
You will need a credential for this type of accommodation. If you haven't got one, buy it on this website
https://www.santiagodecompostela.me...passport-from-the-pilgrims-office-in-santiago
The only other accommodation type is the ones with an A in the Prix column: the price in this case is up to CHF30.
Please let me know if you need any other explanation.
Hope this helps.
Bon Chemin!
Andrew