Related Rule
Practice Relating to Rule 75. Riot Control Agents
In 1931, during the League of Nations Preparatory Commission for the Disarmament Conference, France, in a note regarding a memorandum submitted by the United Kingdom, stated:
I.All the texts at present in force or proposed in regard to the prohibition of the use in war of asphyxiating, poisonous or similar gases are identical. In the French delegation’s opinion, they apply to all gases employed with a view to toxic action on the human organism, whether the effects of such action are more or less temporary irritation of certain mucous membranes or whether they cause serious or even fatal lesions.
II. The French military regulations, which refer to the undertaking not to use gas for warfare (gaz de combat) subject to reciprocity, classify such gases as suffocating, blistering, irritant and poisonous gases in general, and define irritant gases as those causing tears, sneezing, etc.
III. The French Government therefore considers that the use of lachrymatory gases is covered by the prohibition arising out of the Geneva [Gas] Protocol of 1925 … The fact that, for the maintenance of internal order, the police, when dealing with offenders against the law, sometimes use various appliances discharging irritant gases cannot, in the French delegation’s opinion, be adduced in a discussion on this point, since the Protocol … relates only to the use of poisonous or similar gases in war. 
France, Note by the French Delegation to the League of Nations Preparatory Commission for the Disarmament Conference regarding a British Memorandum, reprinted in League of Nations Doc. C.4.M.4. 1931, IX, Documents of the Preparatory Commission for the Disarmament Conference, Series X, Minutes of the Sixth Session (Second Part), 15 January 1931, p. 311.
[emphasis in original]