A quick update on this post. I'd like to give an example of what I mean by a rebate program to help stimulate the housing market.
Example. Adam and Barbara are a thirty something couple with a combined income of 48,000 euros per year. They have two children, and want to buy a house for their growing family. This family will pay approximately 14,000 euros in income tax this year.
If we allow them to offset the cost of mortgaging a new property against these (already paid) taxes, the government effectively increases Adam and Barbara's incomes by, say, 10,000, and only in the direction the government wants: funneled through the housing market. The tax rebate does not apply for other purchases and at other times.