The issue of the influence of norms on behaviour is as old as sociology itself. Institutional theorists, such as Selznick (1957), theorized this influence in terms of “precarious values”. This paper uses this classical view to bring in structure between norms and behaviour. To do this, we explore the selection effect (Snijders, 2001,2005) of a conflict of norms (a controversy) on the evolution of the advice network among lay judges at the Commercial Court of Paris and on their decisions. We use a jurisprudential case about unfair competition (material and “moral” damages), a case that we submitted to all the judges of this court. The controversy among them is about the extent to which they should be “punitive” in awarding damages, especially “moral” damages. We examine the criteria and norms that they refer to in their discretionary decision making in this case. Statistical analyses using Siena combine longitudinal advice network data collected among them with their normative dispositions. We show that, in spite of declaring themselves to be punitive, the majority of judges align themselves on judges with a law degree coming from the banking industry, who tend to be non punitive. We measure and model the selection effect of this norm on the evolution of the network, teasing out a “preferential attachment” effect in which bankers with a law degree become ever more central over time in these networks. This allows them to exercise a strong influence on the court’s judicial decision making. We argue that this approach of conformity and alignments in controversies provides new insights into the relationship between norms, structure and behaviour.