AZF was the name of a chemical factory in Toulouse, France, which exploded on 21 September 2001. The blast was equivalent to 20-40 tons of TNT, producing an earthquake with a magnitude of 3.4, and was heard 80 km away. The incident resulted in 31 deaths and left 2,500 wounded. Damages paid by insurance companies exceeded 1.5 billion euros.

Toulouse is the prefecture of the French department of Haute-Garonne and of the larger region of Occitania. The city is on the banks of the River Garonne, 150 kilometres from the Mediterranean Sea, 230 km (143 mi) from the Atlantic Ocean and 680 km (420 mi) from Paris. It is the fourth-largest city in France after Paris, Marseille and Lyon, with 504,078 inhabitants within its municipal boundaries (2021); its metropolitan area has a population of 1.5 million inhabitants (2021). Toulouse is the central city of one of the 22 metropolitan councils of France. Between the 2014 and 2020 censuses, its metropolitan area was the third fastest growing among metropolitan areas larger than 500,000 inhabitants in France.