Norms in multi-agent systems are used as a mechanism to regulate the behavior of autonomous and heterogeneous agents and to maintain the social order of the society of agents. Norms define what is permitted, prohibited and obligatory. One of the challenges in designing and managing systems governed by norms is that they can conflict with another. Two norms are in conflict when the fulfillment of one causes the violation the other and vice-versa. Several researches have been proposed mechanisms to detect conflicts between norms. However, there is a kind of normative conflict not investigated yet in the design phase, here called runtime conflicts, that can only be detected if we know information about the runtime execution of the system. This paper presents an approach based on execution scenarios to detect normative conflicts that depends on execution order of runtime events in multi-agent systems.