Prior to World War I, Russia was part of the Triple Entente, an alliance with France and Great Britain. As one of the major belligerents in the war, Russia played a significant role on the Eastern Front, where it fought against the German and Austro-Hungarian armies.
However, in February 1917, the Russian Revolution broke out, leading to the overthrow of the Romanov dynasty and the establishment of a provisional government. The provisional government continued Russia's participation in the war, but its authority was weak, and the country was plagued by political instability and economic collapse.
In November 1917, the Bolshevik Party, led by Vladimir Lenin, seized power in a second revolution. The Bolsheviks sought to end Russia's involvement in the war and pursued peace negotiations with Germany. In March 1918, the Bolshevik government signed the Treaty of Brest-Litovsk with Germany, formally withdrawing Russia from the war and ceding vast territories to Germany in exchange for peace.
Despite Russia's withdrawal from the war, it still had an interest in the peace conference, as it sought to protect its territorial interests and secure a say in the post-war settlement. The Bolshevik government sent a delegation to the peace conference, led by Leon Trotsky, the Commissar for Foreign Affairs.
However, the Allied Powers were reluctant to recognize the Bolshevik government as the legitimate representative of Russia. They insisted that the pre-revolutionary Russian government, or a non-Bolshevik successor government, should participate in the conference. As a result, the Bolshevik delegation was not allowed to sign the Treaty of Versailles, the main peace treaty that ended the war.
The Paris Peace Conference and the Treaty of Versailles were largely driven by the interests and perspectives of the victorious Allied Powers. Russia's absence from the major decision-making processes left a significant impact on the post-war order and contributed to the country's strained relations with the Western Allies in the years that followed.