Special Characters usable in backend but not visible in frontend

For a shop in a Dutch and German language w'eve experiencing problems with special characters foor the German version. In the backend we can use all special characters we need (such as the German Ringel S = ß) but in the frontend they wil not show up. The store is just renewed from version 2 to the latest 3 version. Yesterday we enabled a script for new products and there we have the same problems. In the backend everythings shows correct, in the frontend we don't see any special characters.

Does anayone know this problem and even better has a solution.

Thank you in advance.

Paul van der Sande