At first the authoress explains the theory of the appearance as it is recognized by the French judge, to analyze, secondly, the applicability of this theory in the Polish legal system. In France, among the most prevalent examples of the application of the theory of the appearance are: the apparent ownership, the apparent mandate, the heir apparent and the simulation. The theory of the appearance should be understood as an independent basis for the creation of the legal consequences consistent with the legitimate expectations of the person who trusted the appearance created by another person. In the Polish law, there are few legal exceptions that allow, in specific situations, the acquisition of rights by the person who trusted the appearance, as for example, the acquisition of property on the basis of the Article 169 of the Polish Civil Code and the effectiveness of the apparent transaction in the benefit of the third party acting in good faith in case of simulation, as it is allowed on the basis of the Article 83 § 2 of the Civil Code. As for other cases, unforeseen by the legal rules, the authoress makes some proposals: the application by analogy of the Article 83 § 2 of the Polish Civil Code and the interpretation by the courts of the statements of intent within the spirit of protection of legitimate expectations. The authoress proposes as well legislative amendments that would seek the inclusion in the Civil Code of a general regulation to protect the good faith.