The discovery was made at a former cinema hall in the town of Verona, about 75 miles west of Venice.
Archaeologists say the building, which dates back to the second century, is believed to have survived a fire because its roof had collapsed and it contained a number of items of charred wooden furniture.
Experts say it is not yet clear what purpose the building served.
Although the structure had been damaged in the fire, some of the interior was "preserved intact, with the magnificent colours of the frescoed walls dating back to the second century,” said Verona’s archaeological superintendent, the department in charge of archaeology for the area.
It was found while renovations took place at the Astra cinema site, which has been vacant for around 20 years.
The discovery and evidence of the fire evoked memories of ancient Pompeii, the superintendent added.
Pompeii was destroyed in around AD79 when Mount Vesuvius erupted, burying its residents under ash and rock.
The nearby town of Herculaneum was also destroyed following the volcano blast.
Earlier this year, a ceremonial chariot was discovered during excavations of a Roman villa just outside the walls of ancient Pompeii.
The four-wheeled vehicle made of wood and iron with decorations in bronze and tin was almost perfectly preserved when the city.
It was unearthed in the portico opposite the stable where archaeologists found the remains of three horses, including one still in its harness, in 2018.
Italy's culture ministry described the carriage as "a unique find, without any precedent in Italy".
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