The essay analyses the conditions in which private economic initiative creates an economic system based on free competition, giving rise to the presuppositions of civil democracy. In particular, the attention of the European and Italian juridical order aims to guarantee the effectiveness of the principle of substantial equality in contracts, so as to remove any informative asymmetries among the parties of the relationship, thus creating an equal and economically efficient exchange. In this perspective, the law of contract clearly assumes a regulatory function of the market, preventing potential abuses of contractual power which might compromise its real competitiveness.