In November I showed a row of jacarandas in full bloom. Keen-eyed observers of yesterday's photo of the Town Hall may have noticed that the trees out the front are jacarandas in full leaf. Here's a close-up of part of the building with one of the trees.
Sydney Town Hall is very "hotel de ville" French, and it does indeed have Italianate, and Second Empire French beaux arts influences. There's some history of it to be read here.