Studying developments of mistake theory in Contracts as reformed by the French Civil Code in 2016

A mistake in the contract is a misconception of the parties or one of them about one of the elements of the contract. In the civil codes, Mistake nature and condition is usually described as a part of intention and consent title. Following the amendments in the French Civil Law (Contracts Law section) in 2016, the Mistake regulations were changed. This transformation was significant because Napoleon's code articles remained intact over the past two centuries, and interpretations by courts and lawyers in this regard have led to the formation of a different approach to the Code texts in the Mistake section; According to Articles 1130 to 1136, and then 1139 and 1144, the mistake rules are relatively more detailed than in the past. Innovative topics Such as descriptions of the circumstance that is a ground for nullity clarified of essential qualities in a contract, mistake in the subject or the law, also in the subject and the contractual person, a mistake in the motivation and mistakes caused by the fraud. Some kind of neutral errors such as mistakes in the evaluation and motivation are mentioned. The French Civil Code (1804) is the most important source of adaptation of Iranian civil law in the general rules of contracts; therefore, any review in this section can be effective in providing new interpretations for Iranian code and inspiring its reform. In this article, an effort has been made to provide a relatively accurate analysis of the current Mistake theory of French civil law.