Constitutional practicability of referendum on EU Constitution

No. Binding referendum requires implementation by constitutional amendment. Consultative Referendum can anyhow be held if ordered by ad-hoc-law.

Regulation about a special transfer of sovereignty to EU

none

Approval of transfer of sovereignty without effect of constitutional amendment

Majority of votes from both chambers, Art. 91 I, 67 II ConstNet.

Approval of transfer of sovereignty with effect of constitutional amendment

Majority of 2/3 of the votes from both chambers, Art. 92, 91 III ConstNet.

Approval of constitutional amendment

Majority of 2/3 of votes from both chambers after a law declares the necessity of a constitutional amendment, the disbandment of both chambers and their re-election, Art. 137 ConstNet.

Other constitutional regulations about referendums

none