If a profit is made on the sale of the property, it must be taxed. In this case, the speculation tax is due, which is always based on the individual tax rate.
However, the tax is not due in every case. It can be saved even if the house was rented. The sale of a property can be tax-free if the property has been used for own residential purposes at least in the last two years before the sale. Even shared use by another person, such as a partner or a spouse, does not prevent self-use.