Copyright agreement with the artist who will be comissioned to build it. Simple. Have it set up by a lawyer if the plans are for publications as well, such as in books, magazines, selling t-shirts etc.
Otherwise, if it is in a public place, it is the so called Panoramafreiheit for photos - this link is in German, but look for it with Google under 'Monumentfreedom' for the english version.
Copyright agreement with the artist who will be comissioned to build it. Simple. Have it set up by a lawyer if the plans are for publications as well, such as in books, magazines, selling t-shirts etc.
Otherwise, if it is in a public place, it is the so called Panoramafreiheit for photos - this link is in German, but look for it with Google under 'Monumentfreedom' for the english version.