Serbian-Hungarian Baranya-Baja Republic (Српско-мађарска република Барања-Баја, Baranya-Bajai Szerb-Magyar Köztársaság) - August 14, 1921 - August 25, 1921.
"The Serb-Hungarian Baranya-Baja Republic was a short-lived, Soviet-oriented mini-state, proclaimed in Pecs on August 14, 1921, on occupied Hungarian territory during the peacemaking aftermath of the first World War, tolerated and fostered by the newly-proclaimed Kingdom of Serbs, Croats and Slovenes. Its territory included the geographical region of Baranya and the northern part of Backa region.
After the military defeat of Austria-Hungary in October 1918, the territory of Baranya came under control of the Serbian army and was administered by a people's administration from Novi Sad. Since the defeat of Bela Kun's Hungarian Soviet Republic in summer 1919, many communist dissidents from Budapest, escaping from the "white terror" of admiral Horthy, emigrated to Baranya, where Bela Linder, mayor of Pecs, gave them refuge.
The peace conference in Paris assigned Baranya to Horthy's Hungary and news about this decision were followed by general strike and mass demonstrations in Pecs against the decision, which culminated in Great People's Assembly on August 14, where in front of 30,000 people painter Petar Dobrovic suggested the formation of independent republic that would include region of Baranya and northern part of Backa around Baja. Since his suggestion was accepted by the people, Petar Dobrovic became president of executive committee of the new Republic.
However, the authorities of the new republic did not manage to gain international recognition of their independence, and since the republic was under protection of the Serbian army, after withdrawal of this army from Baranya, Horthy's forces entered into region and put an end to the Republic.
On August 21-25, 1921, the territory claimed by the Republic was divided between Hungary and the Kingdom of Serbs, Croats and Slovenes (the later Yugoslavia; notably the part that today is part of the republic of Croatia), as was previously decided by the Treaty of Trianon of 1920.
Most of the inhabitants of the republic were ethnic Hungarians, while other ethnic groups that lived in the area included Serbs, Croats, Sokci, Bunjevci, Germans, Jews, Romanis, Banat Romanians, Germans, Slovaks and others.
The President of the Executive Committee (14 - 25 August 1921), i.e. president of the republic, was Petar Dobrovic (1890 - 1942), an ethnic Serb (Hungarian-born) and noted artist (painter)." (wikipedia)
The Czech, Hungarian and Italian wikipedias present the Serbian flag (plain) as the flag of this republic. There is a site on the net - 'Balkanforum' (in German language) which also shows the Serbian tricolor for Baranya-Baja Republic.
Ben Cahoon' s 'Worldstatesmen' site has it in the Hungarian colors, for a change of palette.
I've two small and grainy photograph of the mass rallies in Pecs after the proclamation of the republic, but it is impossible to see the flags in them.
It is also possible the republic used the plain red flag, just like the one of the Hungarian Soviets, considering its ideological orientation.
