Bulgaria and the Euro: Why a Referendum Is Legally Impossible

The Constitutional Court has already announced that it will rule on the issue raised by President Rumen Radev regarding a potential referendum on the euro. Meanwhile, public debate continues to escalate, both online and in street protests that frame the euro as a threat to Bulgaria’s national currency. Demonstrators across the country are calling for the resignation of the government and demanding a referendum on whether to adopt the euro, even though it's unclear what danger actually threatens the Bulgarian lev.

Calls for public consultation on the single European currency are not new. The idea resurfaced recently after President Radev criticized Parliament Speaker Natalia Tsoneva for refusing to admit for discussion the referendum proposal he submitted. Still, the topic has sparked renewed attention, particularly on social networks, where claims about referendums held in other countries are often circulated - claims that are largely misleading.

European Commissioner for the Economy Valdis Dombrovskis, who visited Bulgaria after the publication of EU and ECB convergence reports, clearly stated that no country has held a referendum on adopting the euro. He also confirmed that Bulgaria has met the necessary criteria to join the eurozone starting in January 2026.

Is such a referendum even legally possible? According to Assoc. Prof. Dr. Yulia Zaharieva from Sofia University’s Faculty of Law, the answer is no. As she explained to Club Z, Bulgaria accepted the full body of EU law upon accession, which includes a commitment to adopt the euro once the country meets the necessary conditions. This position has been upheld by the Constitutional Court. In Zaharieva’s view, current political calls for a referendum are legally groundless and serve more to stir public emotion than to pursue lawful action.

Zaharieva adds that adopting the euro is a highly technical matter that requires deep expertise, not a simple yes-or-no question for a general public vote. She warns against misinterpretations of what happened in other EU countries, where referendums were held on joining the EU - not specifically on switching to the euro.

Indeed, 20 EU countries now use the euro, and none held referendums on adopting it. Countries such as Germany, Belgium, the Netherlands, Italy, Spain, Portugal, Greece, Cyprus, and Luxembourg proceeded without consulting the public on the currency. Others, like Austria, Finland, Slovakia, and the Baltic states, held referendums on joining the EU, which indirectly implied future euro adoption. Only France and Ireland held referendums related to the Maastricht Treaty—the legal foundation for the monetary union.

Denmark and Sweden are often cited as counterexamples. However, Denmark secured an official opt-out from the eurozone during Maastricht negotiations following a public vote rejecting the treaty. Sweden held a referendum in 2003 and opted not to adopt the euro, despite technically being obliged to do so under EU law - a political rather than a legal stance.

Bulgaria and Romania, for their part, never held public votes on joining the euro. Zaharieva stresses that upon entering the EU in 2007, Bulgaria agreed to eventually adopt the euro once it fulfilled the convergence criteria. No specific deadline was set, but the commitment was made. This is why references to an explicit clause stating that “Bulgaria is obliged to adopt the euro” are redundant - the obligation is already embedded in the terms of accession.

She further notes that Article 5 of Bulgaria’s Accession Treaty reinforces this interpretation. The country joined the EU with a so-called “derogation,” meaning it delayed adopting the euro only until it met the required benchmarks. This mechanism was used for practical readiness, not political autonomy.

Misleading claims about the euro often flood public discourse and social media, twisting the meaning of European treaties. According to Zaharieva, such manipulation is not only unhelpful but undermines public understanding of Bulgaria’s actual obligations under EU law. She cautions that pretending Bulgaria can now “decide” whether to adopt the euro ignores the legal reality of its 2007 commitment.

She recommends a recent publication titled “The Euro and EU Countries: Where Are We?”—a comprehensive 500-page book with studies, charts, and analysis that break down the euro’s status across the EU. The book, co-authored by Associate Professor Kaloyan Simeonov, is available online and free of charge for those who seek a factual understanding of the eurozone and referendums.

Looking ahead, the Eurogroup will meet in Luxembourg to review the EC and ECB reports. This will be followed by consultations with the European Parliament, and in early July, final legislative decisions are expected for Bulgaria’s entry into the eurozone.

In conclusion, no EU member state currently using the euro held a referendum specifically on adopting the currency. Referendums did occur on EU membership or related treaties, but not on the euro itself. In Bulgaria’s case, the legal obligation to adopt the euro was made in 2007. While political noise continues, the legal path forward remains clear.

Source: Club Z