Outline: Going to rewrite this, more or less, with mostly French sources, because I got too lost in the material to keep things straight. English sources are mostly useless but will still be consulted.
On 23 March 2018, there was a series of Islamist terrorist attacks in the towns of Carcassonne and Trèbes in southern France. Redouane Lakdim, a 25-year-old French Moroccan (born 11 April 1992 in Taza, Morocco), shot the two occupants of a car in Carcassonne, killing the passenger and hijacking it. He then opened fire on four police officers, seriously wounding one. Lakdim drove to nearby Trèbes, where he stormed a Super U supermarket, killing two civilians, wounding others, and taking at least one hostage. He swore allegiance to the Islamic State and demanded the release of Salah Abdeslam, the only surviving suspect of the November 2015 Paris attacks.
A senior gendarmerie officer, Lieutenant Colonel Arnaud Beltrame, voluntarily swapped places with a hostage. After a three-hour stand-off, Lakdim shot and fatally stabbed Beltrame. A police tactical unit immediately stormed the building and killed Lakdim. He was named a "soldier of the Islamic State" by the Amaq News Agency, and the President of France called the attacks an act of Islamist terrorism. Five people were killed in the attacks, including the perpetrator, and fifteen were wounded.