When a person is obliged to do an act , performing this agreement and obligation is considered as one of his legal , social and moral duties. Therefore if this obligation is not performed by the person , common sense orders to compensate the damages made. In some contracts , the parties previously  determine the amount of the damage caused by not performing the obligations. This contractual term is called penalty clause in Irans law.

The following are the most important subjects that have been considered by the author :

Firstly : the possibility of demanding the penalty clause , included in contracts and the quality of demanding that.

Secondly : the necessity of proving  the damage in demanding the penalty clause.

Thirdly : the difference between the penalty clause and other similar institutions , and the conditions and the effects of the penalty clause included in contracts.

Forthly : the possibility of penalty clause adjustment and the quality of decreasing or increasing it in foreign law systems.

It seems that Irans law suffers from a legal gap in the sphere of penalty clause and regarding the extensiveness of these terms in clauses of contracts and the increasing use of it , it is essential to pass proper legal texts in this field . At last , an amendment to the article 230 of Irans  civil law is suggested