Here is some info on the coin: http://www.union-latine.com/lang-en/1-2-franc/151-demi-franc-1906.html Not sure about value, may want to see if any are being sold on ebay or other auction sites and see what they are going for.
Switzerland 1/2 Franc catalog-# KM#23 weight- 2.5 g .835 silver 1906-B mintage-1,000,000 grade/value F-$2.50 VF-$4.00 XF-$23.00 UNC-150.00 BU-$275.00 B mint mark=Bern. I am guessing your coin is either F-VF or in between.
I'd grade that as G8 to F12. Any value is in the metal content, as they unfortunately made a TON that year. Some Swiss coins have surprisingly high (book) values. This time it goes the other way.
