Calabresi and Melamed delivered a powerful theory to explain, under what conditions it is economically efficient to transfer a property right by voluntary and alternatively by involuntary transactions. In the first case the property right should be protected by a property rule or an injunction as well as by criminal sanctions and in the second case only by a liability rule. Their theory is normative in the sense that they defend involuntary transactions under certain conditions and voluntary transactions under other conditions. But their analysis is also analytical insofar as it predicts an evolutionary pressure on legal norms to encourage voluntary or involuntary transactions if the conditions, which they identified, are met. This article describes two legal changes in opposite directions in Germany. In nuisance law the development was from voluntary to involuntary transactions and in privacy law it was from involuntary to voluntary transactions. We try to make it clear that these developments were triggered by the underlying causes which Calabresi and Melamed identified in their seminal paper on property rules versus liability rules.