Die Gegenleistung im Vertrag – Gegenstand, Grenzen und Vertragsrisiko

The author undertakes a fundamental analysis of counter-performance as a structural element of contractual exchange. Traditionally, contract law has focused on the contractual performance, while the concept of counter-performance remained conceptually underdeveloped. This perspective has changed fundamentally in the process of digitalisation and the introduction of new remuneration models based on the provision of personal data instead of a monetary payment. The study traces the foundations of this development in civil law, data protection, and EU law, paying particular attention to the Directive 2019/770, the first legislative act to explicitly recognise data as a form of consideration. Building on these foundations, the author categorises the legal limits on counter-performance imposed by mandatory contract law. She distinguishes between rules that safeguard party autonomy and those that pursue distributive objectives beyond the individual contract, such as rent control or minimum wage legislation. On this basis the author develops proposals on the potential evolution of contract law to address new forms of data-based consideration. The final part examines the significance of counter-performance for the allocation of contractual risks. Drawing on the emphasis placed by the German Federal Court of Justice on the »equivalence of performance and counter-performance«, the author demonstrates how changes in equivalence influence the ongoing structure of the contractual exchange. The study thus offers a comprehensive reassessment of a fundamental concept of contract law.

Einleitung
Teil 1: Die Gegenstände der Gegenleistung
§ 1. Leistung und Gegenleistung in der Regelungskonzeption des BGB
§ 2. Gegenstände der Gegenleistung
Teil 2: Die Grenzen der Gegenleistung
§ 3. Die Gegenleistung im Verhältnis von Privatautonomie und zwingendem Vertragsrecht
§ 4. Grenzen der Gegenleistung und die Gewährleistung der Vertragsfreiheit
§ 5. Preisgrenzen - Die Gegenleistung als Gegenstand zwingenden Vertragsrechts
§ 6. Grenzen datenbezogener Gegenleistungen
Teil 3: Die Gegenleistung und das Vertragsrisiko
§ 7. Die Gegenleistung im Vertragsvollzug
§ 8. Besonderheiten bei konditional verknüpften Leistungspflichten
Zusammenfassung