The family, as the root cause of many problems in society, has always needed to be studied and re-read. One of the significant capacities and dimensions of the family legal system in Islam is the presence of a contract from the formation of the family until the dissolution and the period after the dissolution. An efficient jurist cannot neglect to ponder and re-read this capacity. Perhaps through this reading, the Family Law Organization in Iran will help the community management in solving emerging family problems. On the other hand, the comparison of this study with a long-standing legal system such as the French family law system will add depth to the research. Contractualization is the subject of the current reflection of French law on the evolution of the family. Individualism, fundamentalism, and distancing oneself from institutionalism and imperative rules are the source of this trend. In contrast, the family in Iranian law, given its Islamic origins, has a serious relationship with the contract. Observing areas of family law that are contractual and non-contractual, leads the researcher to test the extent of Iran's family law tendency to contract, its foundations, and to examine the flow of the principle of contractual freedom with different interpretations. Hence, the subject of the dissertation was called contractualism and the comparison of this concept in Iranian and French family law. Proper knowledge of non-contractual areas and protection of its capacities according to the sacred dimension of the family, can protect the Iranian family law while enjoying the benefits of the contract from the damages of currents like contractualization.