Issues of sub-national referendums regulated at the national level

Germany, Constitution (as amended in 2020), accessed 8 September 2022

Article 29 [New delimitation of the federal territory]

(1) The division of the federal territory into Länder may be revised to ensure that each Land be of a size and capacity to perform its functions effectively. Due regard shall be given in this connection to regional, historical and cultural ties, economic efficiency and the requirements of local and regional planning.

(2) Revisions of the existing division into Länder shall be effected by a federal law, which must be confirmed by referendum. The affected Länder shall be afforded an opportunity to be heard.

(3) The referendum shall be held in the Länder from whose territories or parts of territories a new Land or a Land with redefined boundaries is to be established (affected Länder). The question to be voted on is whether the affected Länder are to remain as they are or whether the new Land or the Land with redefined boundaries should be established. The proposal to establish a new Land or a Land with redefined boundaries shall take effect if the change is approved by a majority in the future territory of such Land and by a majority in the territories or parts of territories of an affected Land taken together whose affiliation with a Land is to be changed in the same way. The proposal shall not take effect if, within the territory of any of the affected Länder, a majority reject the change; however, such rejection shall be of no consequence if in any part of the territory whose affiliation with the affected Land is to be changed a two-thirds majority approves the change, unless it is rejected by a two-thirds majority in the territory of the affected Land as a whole. […]

Mergers or re-arrangements of territories of regional states are regulated by Article 29 ofthe Basic Law (constitution) of Federal Republic of Germany.