Peacekeeping operations Nowadays, most wars have two common features, seemingly contradictory: they are intrastate conflicts, and they are a globalized phenomena. These characteristics result in very complex scenarios, which involves civilians as irregular fighters or war crime victims, and are related to internacional policies and geopolitic strategy of the global powers. As a consequence, foreign intervention in armed conflicts is accepted more than ever, owing to humanitarian reasons. Moreover, this class of military action is mandatory due to international treaties, like the Resolutions adopted by the United Nations Security Council. Even though overseas armed interventions are badly considered by the public opinion of most countries, the peacekeeping missions still seem to be a reasonable use of military force, specially when civil population is affected by the fight or war crimes are being commited. Therefore, modern armed forces must be prepared not only to be involved in unfamiliar scenarios, but also to fight a different battle for the public opinion in their own nations. Mastering of different languages, lore of different cultures and religions or knowledge in Human Rights or International Law are valuables among the ground troops. In these state of things, the existence of military nature police agencies such as the French Gendarmery is priceless - members of the institution are able to operate in a war, integrated in international coalitions, and in postwar, instructing local law enforcement agencies in methods respectful with Human Rights.