A bunch of cities around the world are trying something similar out. Where I’m at, in Vancouver, an empty homes tax came into affect almost a year ago. The goal isn’t to explicitly bring down property values, but rather to help out with rental prices and cost of living in general. It seems like it’s working.
Anecdotally, I have some friends who are now renting previously empty luxurious home near the beach with a pool and a three car garage for less money than their previous digs. They certainly lucked out, but apparently, this tax is bringing more rentals to market and bringing down costs.