Collective Enforcement In The Digital Single Market: Converging Paths Of Consumer, Competition And Data Law in the European Union

The central argument of the research is that the rise of data-driven markets has profoundly altered the structure of consumer harm, rendering traditional models of individual protection increasingly inadequate and requiring a corresponding shift towards collective forms of enforcement. The first part of the dissertation reconstructs the historical development of EU consumer protection through a series of major turning points. In its original phase, consumer protection was not conceived as an autonomous objective of European integration, but rather as an implicit and instrumental component of market regulation, closely linked to competition law and the functioning of the internal market. The dissertation argues that the current phase emerges with the digital era, characterised by the convergence of consumer law, competition law and data protection law. Within digital markets, personal data acquire a hybrid legal and economic nature, functioning simultaneously as a protected fundamental interest, an economic asset and a source of market power. In this context, the traditional informational model of consumer protection — centred on transparency and consent — increasingly reveals its structural limitations. The dissertation demonstrates that data processing in digital environments is often continuous, opaque and largely imperceptible to the data subject, undermining the effectiveness of informed consent as a meaningful safeguard of consumer autonomy. At the same time, digital harms increasingly assume diffuse, cumulative and probabilistic forms, making them difficult to individualise and therefore poorly suited to traditional models of individual litigation. The research further analyses the evolution of EU case law, particularly the role of the Court of Justice in recognising and correcting structural imbalances between consumers and market actors. Several rulings are examined as key steps in the transition from a formal understanding of consent towards a substantive conception of fairness and effective consumer protection. The final part of the dissertation focuses on collective enforcement and comparative analysis. Through an examination of the implementation of Directive 98/27/EC, Directive 2009/22/EC and Directive (EU) 2020/1828 across several Member States — including the Netherlands, Germany, France, Portugal, Sweden, Italy and Austria — the dissertation highlights the significant divergences that persist between national enforcement models. Particular attention is devoted to the Dutch WAMCA system, the German Unterlassungsklagengesetz, the French administrative enforcement framework and the evolving interaction between public and private enforcement mechanisms. The comparative analysis demonstrates that the effectiveness of collective redress depends not only on formal harmonisation, but also on the institutional and procedural infrastructures of national legal systems. The dissertation ultimately argues that the transformation of digital markets requires a corresponding transformation of consumer protection paradigms. The shift from individual to collective enforcement is therefore not merely procedural, but reflects a broader structural evolution in the nature of consumer vulnerability and market power within the European digital economy.