Vigipirate, Plan

   The French homeland security alert system, first set up in 1978 by the government of Raymond Barre. The plan can be activated in the event of a serious risk of terrorist activity, or threat to national security. It has four levels, yellow, orange, red and scarlet. It was first activated in 1991; more recently it was activated at 'red' level in 2004 following the Madrid bombings, in 2005 after the London bombings, and 2005-6 when violence erupted in French suburbs. It is most perceptible by the presence of armed police and soldiers in sensitive locations, such as mainline railway stations, airports, or major institutional buildings.