Texte remanié de: Habilitationsschrift--Rechtswissenschaftliche Fakultät--Innsbruck--Universität Innsbruck, 1990.

When and why can parties escape from a contract on the ground that the price is unfair? This question is considered in a comparative and historical perspective in English and French law. The general rule in both systems is that the parties are free to determine the price and they are then bound by their contract. One well known exception in French law, which derives from Roman law, is Article 1674 of the Code civil which allows a vendor to rescind a contract for the sale of land if the price agreed in the contract is less than five-twelfths of the fair price. It is generally thought that there are no analogous rules in English law. However, the law on this subject is in fact considerably more complex and more colourful than this simple contrast would suggest. Numerous rules on unfair prices in contracts were created in French law by the legislature and the courts since the promulgation of the Code civil in 1804. In English law, courts intervened in contracts on the ground of an unfair price in a few instances in the nineteenth century. However, only the rule on unfair prices in salvage contracts has survived until today. In both systems, the policies of preserving family wealth, protecting weak parties and giving special treatment to certain parties for economic, political, social or cultural reasons underpin these rules. There are two principal conclusions. First, freedom of contract is much less extensive in French law than in English law. This is evident in the numerous rules on unfair prices in contracts in French law and in the primacy of the remedy of altering the price rather than rescission. Secondly, while in theory, French courts play a much less significant role than English courts in the development of law, the creation and abolition of certain rules on unfair prices in contracts by French courts shows that judicial creativity in French law can be much less constrained in practice than in English law.

1 ABSTRACT CHVÁTALOVÁ, Daniela: Contract of Sale in Private Law. [Dissertation thesis]. Charles University. Faculty of Law; Department of Civil Law. Tutor: prof. JUDr. Jan Dvořák, CSc., Head of Department of Civil Law, Vice-Dean for the Doctoral Study Programme and Rigorosum Procedure. Level of professional qualification: Ph.D., Praha: PF UK, 2015. Key words: Civil Code No. 40/1964 Sb. Commercial Code No. 53/1991 Sb. Civil Code No. 89/2012 Sb. Principles of civil law. Purchase. Dual regulation. Precontracting negotiations. Offer and acceptance of the offer. Contract of sale. Purchase of personal property. Purchase of real property. Subject of the contract. Superficies solo cedit. Construction is a part of the land. Hardship clause. Purchase price and manner for determining the purchase price. Commercial terms and conditions. Decrease in a purchase price. Unreasonable decrease in the purchase price Laesio enormis. Price clause. Delivery of goods. Seller's delay in delivery of goods. Transfer of title. Rights in case of defective performance. Quality, quantity, type, and package. Rebus sic stantibus clause. Contractual penalty. Cancellation of a contract of sale. Sale of a plant. Advance payment and retainer. Supranational projects. Draft Common Frame of Reference (DCFR). Principles of European Contract Law...

Le professionnel que l'on croyait capable de défendre ses intérêts, par opposition au salarié ou au consommateur, s'est révélé tout autant victime de contrats déséquilibrés depuis quelques décennies. L'apparition de puissantes entreprises privées dans différents secteurs entraîne, de toute évidence, une inégalité entre les professionnels. Notre étude souligne la complexité de trouver un juste critère pour identifier de manière juste ce qu'est un professionnel partie faible. Il n'est pas possible de dire si, de manière générale, telle entreprise est plus puissante qu'une autre, car la personne morale partie au contrat peut cacher des intérêts difficiles à cerner au premier abord. Le juge ne peut pas non plus être l'arbitre autoritaire des prix sans risquer un détournement de sa fonction. Nous développerons le parti suivant : un contrat entre professionnels est dit d'adhésion lorsque celui-ci n'a pas donné lieu à une négociation idoine ; le juge doit alors s'efforcer de regarder le processus de pourparlers ainsi que les circonstances qui ont précédé la convention. De multiples critères peuvent aider le juge, tels que la taille de chaque entreprise, les parts de marché, les propos échangés par les parties, leur bonne ou mauvaise foi ou encore les efforts engagés par elles. Si le choix de l'analyse des négociations nous apparaît ultimement le plus juste, nous tiendrons cependant compte de ses limites. Il serait illusoire de penser que le juge peut toujours parvenir de manière certaine à connaître l'intégralité des circonstances antérieures au contrat. C'est pourquoi nous ajouterons à l'analyse des négociations un système de présomptions - quoique réfragables - lorsque la disproportion des prestations ou la différence de taille des entreprises ne laisse pas de place au doute. Nous mettrons enfin en lumière les stratégies employées par les parties fortes pour contourner cette analyse des négociations, comme des stipulations néfastes ou une tactique d'internationalisation. Il sera donc préféré une impérativité renforcée en droit national ainsi qu'en droit international. Une fois l'analyse des négociations effectuée, nous essayerons de proposer des sanctions à la hauteur du phénomène. Le juge, selon nous, doit être en mesure de modifier le contrat de façon souple, aussi bien de manière rétroactive que par un changement en cours d'exécution du contrat. Le caractère extrême de certains comportements contractuels nous incite à réfléchir à la possibilité d'un droit pénal plus dissuasif ou bien un droit « quasi pénal » sanctionnant ces comportements de manière plus appropriée. Néanmoins, c'est surtout au niveau de la procédure que se joue la protection contractuelle des professionnels. Un référé ajusté à cet objectif a tout lieu de répondre aux exigences de célérité qui gênent les parties faibles dans leurs démarches. Nous soulignerons aussi l'importance d'un système d'actions collectives qui surmontent efficacement l'écueil du coût du procès. À l'inverse, la sécurité juridique des entreprises nous conduira à proposer une procédure de protection par un système de droit doux. Première partie : L'identification du contrat d'adhésion entre professionnels. Deuxième partie : Le traitement judiciaire des contrats d'adhésion entre professionnels. / The professional, supposed to be able to defend his interests, by opposition to the employee or the consumer, has proven to also be victim of imbalanced contracts for a few decades. The emergence of powerful private companies in various sectors clearly leads to inequalities between professionals. Our study underlines the difficulty to find the best criterion to identify what a professional weaker party is. It is impossible to say that globally such company is stronger than another because the legal person party to the agreement can hide many interests, which are hard to seize at first sight. Nor can the judge arbitrate prices in an authoritarian way without risking a misappropriation of his part. We shall side for this idea: a business-to-business agreement is to be qualified of adhesion contract as long as it does not give place to adequate bargaining; so the judge has to look the bargaining process and the circumstances preceding the contract. Many criteria can help the judge such as the size of the company, market parts, exchanged words, the good or bad faith of the parties or the efforts they have made. If we consider the bargain analysis as the ultimately rightest choice, we have to contemplate its limitations. It would not be realistic to consider that the judge could always discover every circumstance prior to the agreement. This is why we shall join a system of presumptions - albeit rebuttable - to the bargain analysis, when the difference of size of companies or the disproportion of provisions is obvious. We shall put into light the strategies used by strongest parts to bypass the bargain analysis, such as harmful clauses or internationalization tactics. Thus, we shall opt for high obligatory standards, as well as in national law than in international law. Once the bargain analysis is done, we shall try to suggest sanctions adapted to the concern. The judge, in our opinion, must be able to modify the agreement in a very flexible way, either retroactively or during the implementation of the said agreement. The gravity of various contractual behaviors must lead us to think about a form of criminal law or a "quasi criminal" law in order to combat those behaviors in a more suitable mean. Nevertheless, the protection of the professional weaker part is also to be dealt on a procedural ground. A proceeding for interim measures is likely to face the needs for celerity, which bother the weakest parts for their action. We shall also underline the advantages of a class action, which could overcome the financial issue of the lawsuit. Conversely, the legal security of business will bring us to foster a protection by a soft law system. First Part: The identification of the business-to-business adhesion contract. Second Part: The judicial treatment of business-to-business adhesion contracts.