Working Paper on the legal questions of replacing or supplementing the euro in the euro area
According to Siekmann, it is neither legally possible for a member state whose currency is the euro to introduce an new currency instead or parallel to the euro or to obtain a permission from the organs of the EU or the member states to withdraw from the euro area or to implement a parallel currency.
IMFS Working Paper No. 109
Helmut Siekmann
"Replacing or Supplementing the Euro in Member States whose Currency is the Euro"
(PDF, 416 KB)