Answer based on context:

The Attempted coup of 1924 in Estonia , conducted by the Comintern, was a failed coup attempt in Estonia staged by Communists   on December 1, 1924.   Of the 279 actively participating communists, 125 were killed in action, later more than 500 people were arrested. The government forces lost 26 men. During the Soviet occupation of Estonia from 1940 until the era of Perestroika and Glasnost in the Soviet history of the Estonian SSR the communist coup attempt was referred to as Tallinn Uprising of December 1, 1924 against the Yoke of the National Bourgeoisie Government of Estonia and described as an event in the series of World revolution.

What month was the failed coup attempt in Estonia staged by Communists?