On the evening of 13 November 2015, the deadliest terrorist attacks in France's history killed 130 and injured 1,500 people. This particularly complex scenario was aimed at creating ‘widespread panic’: ten assailants armed with assault weapons and explosive belts, divided into three commando squads, committed six attacks throughout Saint-Denis and Paris, including suicide bombings, mass shootings and hostage-taking at the Bataclan theatre/ concert hall. The attacks were still ongoing when President François Hollande spoke live on television. He characterised them as an ‘act of war’ and declared a nationwide ‘state of emergency’.

The following day, the Islamic State of Iraq and Syria (ISIS) claimed responsibility for what began to be called the ‘French 9/11’. Details emerging in the press suggested that most assailants were already known or closely watched by French or Belgian intelligence services. Soon, their German, Greek and Turkish counterparts explained that they also had significant information on some of the assailants and their whereabouts and had unsuccessfully tried to warn the French about the jihadist returnees’ intentions to travel to France. As former Central Intelligence Agency (CIA) Director John Brennan stated: ‘We knew the system was blinking red. We knew just in the days before that ISIS was trying to carry out something.’

Seven years, a parliamentary investigation and two historic trials after the attacks, the conclusion is irrevocable: in retrospect, the amount of information suggesting that a major attack was about to happen is staggering. Why did French intelligence services fail to foresee the attacks when they seemed to have had so much information?