Here is the info from German Customs for shipping art that will be shipped back to you:
Dear Sir or Madam,
Goods intended to be shown at a fair or an exhibition could be imported in temporary admission. Generally you/the importer do/does not pay duty or tax, but a deposit (see below for details).
If you/they receive an ATA carnet from the relevant association of their home country, you/they could use this for the import and export declarations. The associations that issue ATA carnets and their costs may be found on http://www.iccwbo.org/chamber-services/trade-facilitation/ata-carnets/. The deposit is already included in the ATA carnet costs.
An ATA carnet is the easiest way to apply for temporary admission. But you/they may also apply for it with a Single Administrative Document (SAD; in Germany form 0747, to be bought), which also has to state place and period of use in Germany. A deposit is obligatory (equivalent to the potential amount of import duty and tax on the imported goods; for handcrafted paintings, drawings or sculptures this would be 7% on the value including transport costs).
When re-exporting the items imported with SAD you/they need an electronic export declaration (e.g. on www.ausfuhrplus.internetzollanmeldung.de) and the "Verwendungsschein" (Form 0790, issued at import).
For language and access reasons I advise that you/they use the help of a customs broker or forwarding agency.
If goods are sent by post or courier service the relevant transporting company should be notified about the temporary admission, and a note should be made on the transport documents and the package to avoid "normal" treatment as import. As far as this answer contains legal statements this information can - for legal reasons - only be given to the best of our knowledge and is non-binding.
(Central Information Unit of the German customs administration)
Postfach 10 07 61
Enquiries in English:
Tel.: +49 351/44834-530
Fax: +49 351/44834-590
By telephone you may contact Central Information Unit
Monday-Friday 08:00 - 17:00
This blog is primarily for exhibition development. It provides ongoing information for artists participating in the upcoming Berlin exhibition. But it's also our tool for interaction, a place where we ask questions, get to know each other, and create an amazing, streamlined exhibition by working more efficiently as a collective.