The enthusiasm engendered by Law and Economics in the conception of the legal policies continues to silence its fatal flaws within the majority doctrine. However, the methodological and empirical inadequacies of a conception of the law in terms of efficiency cannot leave indifferent a well-informed observer of the legal phenomenon, not to mention the reduction of the efficiency of law to its sole economic utility sometimes to the detriment of the traditional ideals of law. This ideological program of economization of law affects the law of contracts where the legal technique is still looking for models capable of explaining the complexity and diversity of the contractual phenomenon. The legal doctrine keeps on recognizing that the notion of contract is an imperfect intellectual construct which evolves with time. In contrast, the economic technique has congealed the contract in one model: the exchange. This hypothesis includes, from the legal theory point of view, numerous presuppositions on the notion of contract, its essence and substance. These preconceptions of the contract by economic theory generate a paradigmatic conflict with the legal theory and above all an axiological conflict with the social function of contract law.