Where is the line between law enforcement and warfare wrt the Chemical Weapons Convention?

Question

As I understand it chemical weapons such as tear gas are prohibited under the Chemical Weapons Convention but allowed in law enforcement, possibly by section 9 (d):

9. "Purposes Not Prohibited Under this Convention" means:

(d) Law enforcement including domestic riot control purposes.

In this world without declarations of war and different intensities of conflict what does this mean in practice?

This is prompted by the news that EU funded weapons were used for domestic riot control purposes including the use of tear gas. The "scandal" as presented is the use of this equipment to "violently suppress recent pro-democracy protests", where is was provided for the purpose of "special intervention unit in the town of Kidira, on the border of Mali, to protect Senegal from potential incursions by armed groups and cross-border crimes, including migrant smuggling".

The question is raises to me is at what point is the use of chemical weapons such as tear gas become a breach of the Chemical Weapons Conversion? When one may be engaging pro-democracy protests, economic criminals such as people smugglers, elements of the state, Wagner mercenaries or as part of an international military mission against Islamist fighters is there a point where it gets "serious enough" that it is no longer legal to use chemical weapons against a "column" of your opponents as witnessed by the twitter video linked in the article?

Answer 1

When it reaches the level detailed in Article 1 of the Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of Non-International Armed Conflicts (Protocol II), 8 June 1977.

1. This Protocol, which develops and supplements Article 3 common to the Geneva Conventions of 12 August 1949 without modifying its existing conditions of application, shall apply to all armed conflicts which are not covered by Article 1 of the Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts (Protocol I) and which take place in the territory of a High Contracting Party between its armed forces and dissident armed forces or other organized armed groups which, under responsible command, exercise such control over a part of its territory as to enable them to carry out sustained and concerted military operations and to implement this Protocol.

2. This Protocol shall not apply to situations of internal disturbances and tensions, such as riots, isolated and sporadic acts of violence and other acts of a similar nature, as not being armed conflicts.

So, basically, when there is an identifiable 'other' side that operates like a military and exercises control over territory.