By examining Iranian jurisprudence and law and articles 1104 and 1163 of the French Civil Code of 2016, it is clear that construction matters and customary matters and contracts are within a wider circle called the realm of compromise. The secret of the disagreement of the jurists in the invalidity of the conditions or matters and construction agreements and the problems caused by it was due to the lack of correct recognition of the position and quality of its connection to the construction of the contract. By recognizing the credit status of agreements or construction matters, disagreements and confusion of topics, rules and works, and the guarantee of its implementation with other conditions in judicial authorities and arbitrations are avoided, and relevant issues are answered in a regular manner that innovation This article and its point of distinction with previous researches are also considered.