1, the parties to the contract can be contractual breach of contract, or not to contractual breach of contract, breach of contract occurs when there is a breach of contract clause priority application of the breach of contract clause, there is no breach of contract clause can only be applied to the breach of contract clause of the law. Just involves the question of whether the priority of application.
2, the legal basis: "the Chinese people's *** and national code" article 577
Party does not fulfill the contractual obligations or the performance of contractual obligations do not meet the agreement, shall bear the responsibility to continue to perform, to take remedial measures or compensation for losses and other breach of contract.
Article 578
If one of the parties expressly indicates or demonstrates by its own behavior that it will not perform its contractual obligations, the other party may request it to bear the liability for breach of contract before the expiration of the time limit for performance.
Article 579
If one of the parties fails to pay the price, remuneration, rent, or interest, or fails to fulfill other pecuniary obligations, the other party may request it to pay.
Article 580
If one of the parties fails to fulfill a non-pecuniary debt or if the fulfillment of a non-pecuniary debt is not in accordance with the agreement, the other party may request for its fulfillment, except for one of the following circumstances:
(1) the performance is not possible de jure or de facto;
(2) the subject matter of the debt is not suitable for compulsory fulfillment or the cost of its fulfillment is excessive;
p>(iii) the creditor has not requested performance within a reasonable period of time.
Where one of the exceptions stipulated in the preceding paragraph prevents the realization of the purpose of the contract, the people's court or arbitration institution may terminate the relationship of contractual rights and obligations at the request of the party concerned, without prejudice to the assumption of responsibility for breach of contract.
Two, the contract must agree to liquidated damages
1, statutory liquidated damages, liquidated damages directly by law for statutory liquidated damages;
2, liquidated damages, liquidated damages are agreed by the parties to the liquidated damages. Agreed liquidated damages is a contractual relationship, called liquidated damages contract. This kind of contract is a subordinate contract. The main contract is invalid, the liquidated damages contract is invalid. Liquidated damages contract is a contract of promise, unlike the deposit contract, not to pay in advance for the establishment of the elements. Agreed that the liquidated damages and a conditional contract, usually, the default occurs, the liquidated damages contract, the default does not occur, the liquidated damages contract does not take effect.