There is an article in the FAZ about possible changes from our Minister of Construction. One can hope.
Subsidizing the purchase of existing houses will rather ensure that the seller side receives more money. If everyone can afford more, the seller benefits. I also consider subsidies for families up to income X to be nonsense, instead of simply raising the tax exemption per child and leaving the rest to the market. These gradations cause distortions everywhere – if you are then 1€ above the threshold, can you afford less than someone below it? Great incentive to work more. Construction prices will fall on their own, either the contractors/tradesmen shut down or they reduce their margins.