Run-time validation of non-functional properties becomes very important to evaluate and keep under control dynamic and evolving systems. Event-driven monitoring is a commonly adopted approach for observing and analyzing that these properties are satisfied. As the events to be observed become more and more complex, a powerful events specification language is needed. In this paper we present a complex events specification language that is included into the Property Meta-Model (PMM). It is intuitive and easy to use and at the same time machineprocessable, thus allowing for the automated run-time configuration of a model-driven event-based monitoring system. The PMM complex events specification language combines features of two existing and well-known event specification languages that are GEM and Drools Fusion, and in addition presents new features not included in the considered languages. As a proof of concept we present how the PMM complex events specification language can be used for modeling complex events excerpted from the scenarios of the CONNECT European Project.