Juliana Republic (1839)
The Juliana Republic was established when rebels from the neighbouring Riograndense Republic (including a young Giuseppe Garibaldi) invaded the Brazilian province of Santa Catarina and took over the city of Laguna. The republic fell apart four months later, mainly because the rebels failed to take over Florianópolis.
The name was adopted because the rebellion took place in July. I’m not sure where the colours come form, but they do resemble the flag of Brazil.