I'm somewhat familiar with the process of buying a house in the United States and I imagine the process is similar in other countries. Normally, the would-be buyer deposits some "earnest money" with a third-party at the time the contract is signed. If the buyer backs out before the closing, he or she forfeits the earnest money and the seller gets to keep it. I understand this to be protection for the seller against a buyer breaking the contract.
On the other hand, does the buyer have any protection against the seller breaking the contract? Sure he or she will get his or her earnest money back but that doesn't provide much disincentive to the sellers to keep their end of the bargain. It's easy to come up a scenario where the buyer would like protection (e.g. they need to sell their old house in order to come up with the down payment on the new house, but they're concerned that after they sell their old house the person they're trying to buy from will back out and they'll have nowhere to live). Is there anything that is done to protect them?