In this article, the conditions and effects of the force majeure in the amendments to the French Civil Code adopted in 2016, in order to use the solutions of the French legislature to eliminate the shortcomings of the Iranian legal system have been studied by descriptive-analytical research method. The main question is what are the conditions and characteristics of the force majeure and what is the criterion for distinguishing them, either personal or relative, and what effect does force majeure have on contracts, contractual obligations and contractual liability? A comparative study of Iranian and French law shows that the inevitability (impossibility of eliminating and repelling the accident) and the unpredictability of the accident, with a kind of relative criterion, and also the impossibility of executing the contract, with an objective criterion, are conditions for the realization of force majeure; But the externality of the accident is not an independent condition and refers to the same impossibility of preventing the accident (not being avoidable). Also, contrary to French law, the Iranian legislature did not anticipate the effects of the force majeure on the contract itself and the contractual obligations, and the effect of force majeure on contractual liability was also incompletely stated, which has led to differences between judicial decisions. Therefore, it is suggested that the legislator, in the form of a Civil Act amendment plan, in Article 227 stipulates the conditions for the realization (characteristics and criteria of distinction) of force majeure and in Article 229, the effects of force majeure on the contract and contractual obligations and compensation for non-implementation or Specify the delay in fulfilling the obligation.