Berlin has such laws since 2014 and it is working poorly. Turns out that it is hard to get an overview of empty apartments. City government has to rely on other tenants reporting empty apartments.

It's already passed in SF for retail [1] and other areas for non-retail.

Further, the revenue from that tax could be used to fund public housing to further drive down housing costs.

[1] https://www.bookweb.org/news/san-francisco-approves-vacant-p...

Netherlands had laws discouraging speculators and hoarders from keeping empty homes:

https://en.wikipedia.org/wiki/Squatting_in_the_Netherlands