@molnibalage
During World War I, France, not Germany as commonly believed, was actually the first nation to use chemical weapons though this was notably a nonlethal tear gas attack (xylyl bromide) carried out in August 1914 against invading German troops. Once the war had degenerated into trench warfare and new methods to attain an advantage were sought, the German Army initiated a chlorine gas attack against the French Army at Ypres on 15 April 1915, initiating a new method of warfare but failed that day to exploit the resulting break in the French line. In time, the more potent phosgene replaced chlorine in use by armies on the Western Front, including France, leading to massive casualties on both sides of the conflict however the effects were mitigated by development of protective clothing and masks as the war progressed.
At the outbreak of World War II, France maintained large stockpiles of mustard gas and phosgene but did not use them against the invading Axis troops, and no chemical weapons were used on the battlefield by the Axis invaders.
Immediately after the end of the war, the French military began testing captured German chemical agent stores in Algeria, then a French colony, notably the extremely toxic nerve agent Tabun. By the late 1940s, testing of Tabun-filled ordnance had become routine, often by using livestock to test effects.[55] The testing of chemical weapons occurred at B2-Namous, Algeria, an uninhabited desert proving ground located 100 kilometers east of the Moroccan border, but other sites also existed.[56][57] A manufacturing facility existed in Bouchet, near Paris, which was tasked with researching chemical weapons and maintaining a scientific and technological vigilance on the subject.[58]
In 1985, France was estimated to have a chemical weapons stockpile of some 435 tonnes, the second largest in NATO following the United States. However, at a conference in Paris in 1989, France declared that it was no longer in possession of chemical weaponry but maintained the manufacturing capacity to readily produce such weapons if deemed necessary.[59]
Fredrik Wetterqvist: French Security and Defence Policy: Current Developments and Future Prospects, p. 105