The Defence Infrastructure Service (Service d'Infrastructure de la Défense or SID) is a French government agency established in 2005. It merged the three former entities in charge of Ministry of Defence buildings and properties: Central Engineers' Directorate, or Direction Centrale du Génie (Armée de Terre), Central Air Infrastructure Directorate, or Direction Centrale de l'Infrastructure de l'Air (Armée de l'Air) Central Directorate of Maritime Properties and Works, or Direction Centrale des Travaux Immobiliers et Maritimes (Marine nationale).