Author: Federica Michelle Rubini
Committee: EU Institutions Committee
Date: 27/05/2026
Established by Council Regulation (EU) 2017/1939 pursuant to Article 86 TFEU, the European Public Prosecutor’s Office (EPPO) is an independent body of the European Union, operational since 1 June 2021. It has a central office at its seat in Luxembourg and operates through a decentralized structure, composed of European Delegated Prosecutors (EDPs), who remain active members of the prosecution services of their national legal orders, acting as the day-to-day investigative arm of the Office across the 24 participating Member States.
The EPPO’s mandate covers offences affecting the financial interests of the Union as defined in the PIF Directive (EU) 2017/1371, including V AT fraud, customs offences, corruption, and money laundering. Moreover, the EPPO is competent for any offences inextricably linked to commission of the “PIF” offences.
By the end of 2025, the EPPO was handling approximately 3,600 active investigations with estimated damage exceeding €60 billion, a significant proportion of which carried a cross-border dimension, according to publicly available EPPO data for 2025.
This cross-border dimension generates a structural tension at the heart of the EPPO’s architecture: the need to gather evidence efficiently across different national legal orders must be balanced against the obligation to protect the procedural rights of suspects and accused persons. The present paper examines this tension through three principal sources:
Article 31 of the EPPO Regulation, which establishes the mechanism for cross-border investigations; the landmark Grand Chamber judgment of the Court of Justice of the European Union (CJEU) of 21 December 2023 in Case C-281/22, G.K. and Others (Parquet européen); and College Decision 052/2024, which revised the EPPO’s operational guidelines on Article 31 in light of that ruling. Reference is also made, where relevant, to the subsequent Grand Chamber judgment of 8 April 2025 in Case C-292/23, which confirms and deepens the Court’s evolving jurisprudence on judicial review within the EPPO framework.
1. Article 31 of the EPPO Regulation: A Sui Generis Mechanism
Article 31 creates a self-standing, sui generis legal basis for cross-border investigations that, as a rule, largely supersedes both mutual legal assistance instruments and mutual recognition tools (most notably Directive 2014/41 on the European Investigation Order (EIO)) in investigations among participating Member States. The premise is that EDPs are colleagues of the same office, not representatives of different sovereign jurisdictions: the “assignment” of a measure from a handling EDP to an assisting EDP is an internal act of the EPPO, not a cross-border request between foreign authorities.Article 31(2) establishes the governing law: the justification and adoption of an assigned measure are governed by the law of the handling EDP’s Member State, while enforcement is governed by the law of the assisting EDP’s Member State. This bifurcation has direct consequences for suspects: the substantive assessment of the necessity and proportionality of, for instance, a home search in Austria, is conducted under German law if the investigation is led by a German handling EDP.
Article 31(3) regulates the mechanism for seeking judicial authorization in case of measures for which this is required either under the law of the Member State of the handling EDP or under the law of the assisting EDP. Where the law of the assisting EDP’s Member State requires a judicial authorization, the assisting EDP must obtain it in accordance with national law; if refused, the handling EDP must withdraw the assignment. Where that law does not require authorization but the handling EDP’s law does, it is the handling EDP who must obtain the warrant from the competent court of its own Member State and transmit it with the assignment. Crucially, Article 31(3) is silent on the scope of judicial review available in the assisting Member State; specifically, whether that court may examine the substantive grounds of the measure or only the procedural aspects of its execution. This ambiguity prompted the first preliminary ruling in the history of the EPPO Regulation.
2. Case C-281/22, G.K. and Others: Efficiency and Charter Rights
In Case C-281/22, a German handling EDP investigating customs fraud involving biodiesel imports assigned searches and seizures of premises in Austria to an Austrian assisting EDP. The Austrian courts authorized the measures, but the suspects challenged them before the Oberlandesgericht Wien (Higher Regional Court of Vienna), alleging insufficient suspicion, lack of proportionality, and violation of their rights under Articles 7 (private and family life) and 17 (property) of the Charter of Fundamental Rights of the EU. The referring court asked whether it could conduct a full substantive review, as in a domestic case, or was limited to procedural aspects of execution.
The Grand Chamber’s response is structured in two parts. The first (para. 72) limits the scope of judicial review in the assisting Member State. Drawing on the wording of Article 31(2), and by analogy with the mutual recognition instruments (European Arrest Warrant, EIO Directive) where the issuing authority assesses substance and the executing authority is bound to execute, The Court held that judicial review in the assisting State must, in principle, be limited to matters of enforcement, rather than extending to a full assessment of the justification and adoption of the measure. A full substantive review in the assisting State would render Article 31 mechanism less efficient than the very instruments it was designed to supersede.
The second and more contentious part, at paragraphs 73 to 75, introduces a Charter-based qualification not found in the text of Article 31. The Court held that the division of competences is without prejudice to the requirements of the Charter: for investigative measures involving a serious interference with Charter-protected rights (searches of private homes (Article 7 CFR), conservatory measures on personal property, and asset freezing (Article 17 CFR)) the Member State of the handling EDP is required to provide, in itsnational law, adequate safeguards such as prior judicial review, ensuring the legality and necessity of the measure. Paragraph 75 reinforces this by reference to Article 31(5)(c), which places on EDPs an explicit duty to safeguard suspects’ rights.
Commentators have aptly described the ruling as a “Solomonic verdict”. The efficiency of cross-border investigations is preserved but at the cost of introducing what appears to be a two-tier system of judicial authorization, one on the merits in the handling EDP’s State, one on enforcement in the assisting EDP’s State, in apparent tension with Recital 72 of the Regulation, which envisaged a single authorization. The scope of “serious interference” also remains undefined: does it extend to searches of business premises, telecommunications intercepts, or financial surveillance? These open questions directly affect the admissibility of evidence and the defense’s ability to mount effective challenges.
3. College Decision 052/2024: Operationalizing the Judgment
On 18 September 2024, the College of the EPPO adopted Decision 052/2024, amending the earlier Article 31 guidelines (Decision 006/2022) to incorporate the C-281/22 ruling and the operational lessons of three years of practice. The Decision pursues uniform application of Article 31 across the EPPO’s decentralized structure.
On judicial authorization, the Guidelines instruct that where both Member States require a warrant, there must be only one authorization on the merits (issued by the competent court in the handling EDP’s Member State, covering justification, adoption, and proportionality) while the court in the assisting EDP’s State reviews only enforcement aspects. On remedies, the Decision confirms that Article 42(1) of the Regulation, entitling any person affected by an EPPO procedural act to challenge it before national courts, applies fully to Article 31 measures, alongside Article 47 of the Charter (right to an effective remedy). On prior judicial review, the Decision incorporates the C-281/22 requirement directly: prior judicial review in the handling EDP’s State is mandatory for measures seriously interfering with Charter rights converting a judicially-derived obligation into binding internal operational guidance.
The Decision also stresses close cooperation between EDPs: since handling and assisting EDPs are colleagues of the same institution, they must coordinate from the earliest stages, discussing the applicable law, authorization requirements, and practical modalities in each State. This relational dimension is central to the EPPO’s efficiency promise, given that the mechanism must be no more burdensome than the EIO it replaces.
4. Subsequent Developments: Consolidation of Judicial Protection within the EPPO Framework
The CJEU’s case law on the European Public Prosecutor’s Office continues to develop around the balance between the effectiveness of cross-border investigations and judicial protection under Article 47 of the Charter of Fundamental Rights of the European Union. The Court has consistently affirmed that procedural acts within EU enforcement frameworks must be subject to effective judicial review where they affect individuals’ legal position, even in the absence of explicit secondary legislation, where otherwise fundamental rights protection would be undermined.In the EPPO context, Case C-281/22 confirms that the division of tasks between the handling and assisting European Delegated Prosecutors cannot reduce the level of Charter protection.
Member States must therefore ensure effective judicial scrutiny of EPPO investigative measures, particularly where fundamental rights are significantly affected. More generally, the principles of equivalence and effectiveness require that EPPO acts are not excluded from judicial review due to national procedural constraints. Where comparable domestic measures are subject to judicial control, equivalent EPPO measures must benefit from the same guarantees in order to comply with Article 47 CFR. Taken together, these developments confirm that the EPPO framework is not a fully harmonized criminal procedure, but an integrated system grounded in national procedural autonomy, limited by EU law principles and Charter guarantees, and ensured in its coherence through the interpretative authority of the Court of Justice.
Conclusion
Article 31 of Regulation 2017/1939 establishes a genuinely novel model for cross-border evidence gathering, one that goes beyond mutual recognition by embedding cooperation within a single institutional framework. The C-281/22 judgment upheld its efficiency rationale while deriving from the Charter an obligation of prior judicial review in the handling EDP’s Member State that the Regulation’s text had left implicit. College Decision 052/2024 gave that obligation operational content. The C-292/23 ruling of April 2025 then confirmed that national implementing laws cannot shield EPPO procedural acts from judicial scrutiny through closed statutory lists. The framework is thus in active judicial construction.
The open questions that remain, the precise scope of “serious interference”, the adequacy of prior review mechanisms in inquisitorial systems, and the case for a legislative reform of Article 31, will shape whether the EPPO’s cross-border reach is matched by equally robust procedural guarantees for those subject to its investigations.
Bibliography / Sitography
EU Legislation
● Regulation (EU) 2017/1939 implementing enhanced cooperation on the establishment of the European Public Prosecutor’s Office (EPPO), OJ L 283/1.
● Directive (EU) 2017/1371 (PIF Directive), OJ L 198/29.
● Directive 2014/41/EU (European Investigation Order), OJ L 130/1.
● Treaty on the Functioning of the European Union, Art. 86.
Case Law
● Case C-281/22, G.K. and Others (Parquet européen), Judgment of 21 December 2023.
● Case C-292/23, Criminal proceedings against I.R.O. and F.J.L.R., Judgment of 8 April 2025.
Institutional Sources
● European Public Prosecutor’s Office, Annual Report 2024, available on the official website of the EPPO.
● European Public Prosecutor’s Office, publicly available data for 2025 (“2025 in numbers” and official communications), available on the official website of the EPPO.
EPPO Documents
● EPPO College Decision 006/2022 (internal guidelines on Article 31).
● EPPO College Decision 052/2024 (revised guidelines on cross-border investigations).