Legal systems in European countries differ greatly, and so does the legal design of collective bargaining. These differences manifest in the importance of constitutional principles, the balance between legislation and collective bargaining, the degree of state influence or voluntarism, the degree of trade union organisation and collective bargaining coverage, and forms of employee representation. But what relationship exists between the law, existing structures, and the methods and mechanisms used in the context of decentralisation? The author finds that structures of collective bargaining are mainly determined by non-legal factors, but the legal form of collective bargaining can help to create and maintain a certain structure and can therefore determine how the process of decentralisation occurs and what instruments and mechanisms are used.