This is already something well-known in the Dutch housing market though. It is known as "zelfbewoningsplicht" (self-occupation.. duty?, e.g. the contract you signed when buying the house stipulates that you, or your direct family have to live in it yourself/themselves). It is usually enforced by "woningcorporaties" (social housing corporations?) with a social mandate and does result in lower prices for the houses/appartements that have it. The odd thing here is that it's now municipalities that are enforcing it on _all_ housing, rather than just on designated social housing. It will be interesting to see the effects though.