This depends on the T&C of the "Gutschein". It might be and it might not be transferable. Compare it to a cheque. A cheque can be issued

• to the "bearer" (good for everybody holding the piece of paper in his hands)
• to the "person named" (not transferable) or
• to the "person named or its order" (transferable by assignment).

And a Gutschein is similar. Under German law a "Gutschein" is a financial instrument. Without knowing the T&S of your "Gutschein" the question cannot be answered.