Let me start my reply with a small apology. The way I phrased my question ("where is that the case?") I might have come across as inconsiderate. I may also have initially misread what you wrote, taking the comment on empty homes a tad too literal. That is, if we count for e.g. unused office space than you are certainly on point.

I believe exactly the opposite. In France and USA we have been giving billions of euros to decades to the construction mafia to build more housing, yet prices keep rising as fast as the number of homeless people. I mean considering that the laws of supply and demand apply to some extent, it makes sense: if millions of landowners voluntarily withdraw their property from the market, you create a speculative bubble where prices cannot go down despite new constructions. If you add to this the fact that any social policies our respective governments had after WWII are actively being dismantled, and social housing in France is now managed like a mafia (where in many places you either pay up under the desk, or wait ~5y on a list) and prioritizing luxury “social” housing in new construction for middle classes, we’re in deep shit. Who profits from “build more”? Big companies and corrupt officials, as always. It will just damage the environment and keep making more people homeless, if those constructions are not tied to an actual social policy.

First of all, when I wrote "build more" I meant to include initiatives such as transforming office space into residential buildings. Sorry if this was not sufficiently implied in my comment. Secondly, I can agree to the notion that the construction mafia needs to be dealt with somehow (i.e. curbing corruption etc.). On your supply and demand remark: many nations in Europe that have housing issues have countrysides that are massively aging and depopulating. Cities in same countries often are growing, but formerly used homes from the smaller places aren't exactly going to transplant themselves into areas where they would be more needed. So, unless jobs etc. are at least partly going back to the smaller towns (to curb urbanization and "spread the load" more evenly across the country), retrofitting existing (office/industrial/retail) buildings and constructing new ones will be the only workable solution. Obviously in conjunction with good social policies. BTW, the building of "social" housing for (lower) middle classes is sometimes done because actual social housing is something they are obviously to rich for. Yet they cannot afford private (either bought or rented) housing and obviously the demand would drive those prices up. So while an imperfect solution, I can see why some regions/cities have chosen to expand the "social" part of social housing (as long as they don't replace actual social housing with it). Especially if at least some of the demand for housing in larger (>200.000) cities is coming from people with a middle income. Not everybody who has difficulties keeping a roof over their head is destitute.

How would it work without police? If we didn’t have a police, we could just find justice without obstacles.

Even when nobody (organised enough to do so) is going to stop thieves, rapists and murderers?

Without an armed militia of psychopaths to enforce injustice, private property would be a pipe dream.

Sorry for asking an ignorant question, but do you mean "property" as in buildings or property in a more literal, broader sense?

We would only have to defend ourselves against owners, and we’re up to that. The issue we face today is if we defend ourselves against an owner attacking us, they will claim we attacked them and we will be condemned by the class justice to prison sentences or fines, despite being the victims (just like victims of police abuse are condemned for “violence” and “insults” against the cops despite being the only ones suffering physical injuries). The police having a monopoly on “legitimate” violence is the reason why the elites and their police get to decide the fate of everyone without suffering any kind of consequences.

I still believe that with good rewrites of the laws and good social policy, many of such issues can be mitigated. I mean, at least half the demonstrations/riots in Europe are organised because of the lack of the former. I think "we" have to start somewhere, but how to reduce police violence further I do not know.