The principle of selling more than one room is stipulated by law.

The principle of selling more than one room is: the house belongs to the party that handles the transfer first, the house that does not handle the transfer first goes to the party that handles the advance notice registration, and the house that does not handle the transfer and advance notice registration goes to the party that actually occupies the house first. The parties to a valid contract have the right to require the seller to perform the contract and deliver the house; The parties to the revocable contract and the parties to the invalid contract have the right to demand the seller to bear the liability for breach of contract.

Legal objectivity:

Article 148 of the Civil Code of People's Republic of China (PRC) * * * If a party commits a civil legal act against its true meaning by fraudulent means, the defrauded party has the right to request the people's court or an arbitration institution to cancel it. Article 209 of the Civil Code of People's Republic of China (PRC) establishes, changes, transfers and extinguishes the real right of immovable property, which shall take effect after being registered according to law; Without registration, it will not take effect, except as otherwise provided by law. Natural resources owned by the state according to law may not be registered. Article 577 of the Civil Code of People's Republic of China (PRC), if one party fails to perform the contractual obligations or the performance of the contractual obligations does not conform to the agreement, it shall bear the liabilities for breach of contract such as continuing to perform, taking remedial measures or compensating for losses.