May I ask how you came across such an affordable property?
I would say that negotiating also plays a role. We are below 1,500 euros/m² construction costs, but have a level of equipment that leans towards luxury*. If I hadn’t negotiated hard back then, we would have paid closer to 1,900.
*Luxury: expensive clinker bricks, the finest roof tiles and interior doors, floors completely of granite and marble, very good electrical equipment and windows, but only according to the Energy Saving Ordinance, without controlled residential ventilation, etc.