From 13 to 19 October 2012, Isabelle Maras, Ph.D candidate at the IFSH, participated as a civil-military adviser (observer) in the EU Crisis Management Exercise Multilayer 2012 (ML12) at the Operational Headquarters (OHQ) in Potsdam. The ML12 was organised by the European External Action Service (EEAS) from 1 to 29 October with the aim to apply the EU Comprehensive approach und thus to put to the test the cooperation between CFSP/CSDP structures and the EU crisis reaction mechanisms. The Commission, the Council, some EU Delegations and Member states took also part in the ML12. It was the first time that such a large-scale EU exercise comprised the different levels of the EU crisis management and crisis reaction – namely the political-strategic (Brussels), strategic-military (OHQ in Postdam) and operational levels (FHQ in Brindisi, Italy).