According to the summary provided by the EASO Courts and Tribunals Network:

The applicant, who holds both Croatian and Serbian citizenship, applied for international protection with regard to the fact that Serbia had requested his extradition in order to enforce his custodial sentence. He claimed that upon his return to Serbia he would face a real risk to his life in Serbian prisons. The administrative authority (the Ministry of the Interior) declared his application inadmissible and terminated the proceedings because the conditions laid out in Protocol No 24 to the Treaty on the European Union on asylum for nationals of Member States of the European Union (hereinafter "Protocol No 24") were not met.

The applicant challenged the decision before the Municipal Court in Prague, which dismissed his action. The court pointed out that since the applicant was a Croatian citizen, provisions of the Protocol No 24 laying down reasons why a Member State (Croatia) could not be considered a safe country of origin were applicable. None of these criteria was met. The fact that the applicant also had another citizenship was irrelevant since it did not alter the fact that Croatia must have been considered a safe country of origin. Furthermore, according to Czech regulations, Serbia is also considered a safe country of origin. The applicant’s objection that he could not voluntarily return to Croatia as his safe country of origin due to ongoing extradition proceedings upon which termination he would be handed over to Serbian authorities was dismissed too. The Municipal Court regarded the extradition proceedings and asylum proceedings as separate and independent of each other.

Subsequently, the applicant filed a cassation complaint. The Supreme Administrative Court ("the Court") ruled that in case a person holds citizenships of State A and State B, it may be sufficient to state grounds for fear of persecution or serious harm only in relation to one of them, provided that the applicant is in a situation in which he is realistically unable to benefit from effective protection of the other state. In such a case, the applicant does not need to assert his claims expressly against both states of his citizenship, since the reasons given in relation to only one of them effectively prevent him from obtaining effective protection in either of them.

In the case at hand, the applicant's possibility of obtaining effective protection in Croatia was purely theoretical. During the international protection proceedings, Croatia could not effectively prevent the applicant's extradition to Serbia. Furthermore, concerning Serbia, designation of a third country as a safe country of origin cannot be, in accordance with the preamble of the Directive 2013/32/EU, an absolute guarantee of the safety of its nationals.

The Supreme Administrative Court stated that it was aware that the annulment of the administrative authority's decision and the decision of the Municipal court may potentially result in granting of international protection to an EU citizen, respectively to a citizen of EU Member State. Yet, the Court emphasized that the applicant did not allege grounds for well-founded fear of persecution or threat of serious harm vis-à-vis the Member State but a third country. The Court concluded that the annulment of both decisions of the Municipal Court and the administrative authority was the only solution compliant with international law obligations, which at the same time did not contravene the EU law.