The Free Territory of Trieste (1947–1954)
en.wikipedia.org
1 thread
possibly related: https://en.wikipedia.org/wiki/Operation_Sunrise_(World_War_I...
They may have happened in the same region, but it looks like Operation Sunrise happened in spring 1945 in the Northern Italian region. Whereas, the Free Territory of Treiste was a microstate artifact of a WWII.