The obligation or duty of confidentiality may be defined as the obligation imposed on a person, either by law or by contract, to refrain from disclosing or communicating certain sensitive information (technical, commercial, financial, or even the existence of negotiations or a contractual relationship), precisely defined and identified as such, to the public or to third parties, on pain of incurring various penalties (mainly civil and criminal). The obligation of confidentiality can therefore be analysed as an obligation not to do or to abstain (not to divulge, reveal or communicate sensitive information), of result, most often unenforceable and whose non-fulfilment is therefore mainly resolved in damages. The purpose of this study is to present the sources and the regime of the obligation of confidentiality (§1), its main debtors within the company in business law (§2), the sanctions attached to its breach (§3) as well as the new regime and the contributions of the law n°2018-670 of 30 July 2018 on the protection of business secrecy (§4).