In this paper, the author refers to the enforcement of contracts based on the principles of private autonomy and good faith. The author refers to aspects like elements and limits of private autonomy; contractual terms; prohibition of selling, according to the Peruvian Civil Code of 1984. The hypothesis consists on determine if the contractual principle of private autonomy is an absolute and unalterable principle, or if on the other hand its action field should be limited by the State with the purpose of avoiding the abuses.