Consumers (Section 13 of the German Civil Code) have a statutory right of cancellation.

Cancellation notice

(1) The customer can cancel the contract within 2 weeks without giving any reasons in text form (e.g. letter, fax or e-mail) or by returning the item. This period begins at the earliest upon receipt of this notice but not before receipt of the goods. This period is deemed observed if the cancellation or the item is dispatched in good time. The cancellation or the return delivery is to be sent to:

Bayerische Verwaltung der staatlichen Schlösser, Gärten und Seen
Schloss Nymphenburg, Eingang 16
80638 Munich, Germany
E-Mail: shop@bsv.bayern.de
Telefax +49 89 17908–190

Consequences of cancellation
(2) In case the cancellation is effective, the performance received on both sides must be returned. The customer must return the goods. Only items that cannot be sent by parcel post shall be collected from the customer.
(3) The customer shall surrender any benefits derived. In particular, he must pay the value for permission to use the item until it is returned. If the customer cannot return the goods in whole or in part or can only return them in a worse state, the customer shall pay compensation for the loss in value. Major deteriorations are particularly soiling of the goods, ripped, removed or damaged pages etc. This does not apply to items provided if the deterioration of such items is solely attributable to the examination thereof - such as would have been possible in a shop. The duty to compensate the loss in value can possibly be avoided if the customer does not use the item like an owner and refrains from anything that could lower the value of the goods.

Return
(4) After the return and receipt of the goods by Bayerische Schlösserverwaltung (hereinafter referred to as SV), SV shall reimburse the purchase price to the customer if the customer has already paid it. The customer shall notify his banking connection to SV for this purpose.
(5) If goods are returned, the customer shall pay the costs for such return if the delivered goods are as ordered.

Exclusion of the right of cancellation
(6) The customer has no right of cancellation in the cases set out under Section 312 d of the German Civil Code, in particular for orders for newspapers and magazines, for goods made according to the customer's specifications or for the delivery of audio or video recordings or software if the data carriers delivered are no longer sealed.