Article 82.
Germany constitutes a Customs and Commercial Union enclosed in a common customs frontier.
The customs frontier coincides with the foreign frontier. Towards the sea the continental coast line with the islands belonging to the Realm forms the customs frontier. Deviations may be admitted where the customs frontier reaches the sea or other waters.
The territory of foreign States, wholly or partly, may be included within the Customs Union by treaty or other agreement.
Parts of the Union may be excluded under special necessity. In the case of free harbours such exclusion can be terminated only by constitutional amendment.
Territories excluded from the Union may be joined to a foreign Union by treaty or by agreement.
All products of nature, industry and art in free circulation within the Realm may be exported, imported, or transited across the frontiers of the Lands or local communities. Exceptions to this may be made by act of the Realm.
Article 83.
The authorities of the Realm shall administer all tariffs and all indirect taxes.[31]
Where the authorities of the Realm administer national taxation, provision shall be made preserving to the Lands their peculiar interests in the sphere of agriculture, commerce, manufacture, and industry.