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Pretty simple WI. Lets say France adopted chemical weapons into its war plans during the interwar period and chemical weapons were used on German forces during the Battle of France.

Assume that it becomes an integral part of France's backup plan. At the most ideal time during the Battle of France, chemical weapons are authorized to be used. France's allies are NOT informed of this during prewar planning sessions.

What happens? Does it manage to blunt or halt the German advance temporarily? Does it prove decisive and allow the Allies time to reorganize and prepare a coherent defense or counterattack? Or is France still doomed to fall? How does it affect the rest of the war?

Germany will obviously retaliate with its own chemical weapons and its nerve agents. However its often stated in chemical weapon threads that in the long run Germany would suffer more from said exchange. Although no matter who wins all of Europe loses. Stalin's the real winner here (unless Germany attacks the Soviet Union).

As a sidenote butterfly, IIRC France apparently had the only gas proof tank during WW2. It was a limited production run so only a few units were created. As a butterfly lets say gas proof capabilities becomes vogue among French tanks in this scenario. Other nations do not make adaptions to their tank designs in response to this.
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