Act No. 51-711 of 7 June 1951 on the obligation, coordination and secrecy of statistics. Available at https://www.legifrance.gouv.fr/affichTexte.do?cidTexte=JORFTEXT000000888573.

Article 6 concerns statistical confidentiality:
Subject to the provisions of Articles 40, 56, 76, 97 and 99 of the Code of Criminal Procedure and those of Article L. 213-3 of the Heritage Code, the individual information contained in the questionnaires bearing the visa provided for in Article 2 of this Law and relating to personal and family life and, in general, to private facts and conduct may not, unless decided by the Archives Administration, after consulting the Committee on Statistical Confidentiality and in respect of a request made for the purposes of public statistics or scientific or historical research, not to be communicated by the depositary service before the expiry of 75 years from the date of the survey or 25 years from the date of the person's death, whichever is the shorter.
A Committee on Statistical Confidentiality is hereby established. This committee is called upon to rule on any question relating to statistical confidentiality. It shall give its opinion on requests for the disclosure of individual data collected pursuant to this Law. The committee is chaired by a Councillor of State, appointed by the Vice-President of the Council of State. It includes representatives of the National Assembly and the Senate. The composition and operating procedures of the committee are determined by decree of the Conseil d'Etat. Beneficiaries of data communications resulting from ministerial decisions taken after consulting the Committee on Statistical Confidentiality undertake not to communicate such data to anyone. Any infringement of the provisions of this paragraph shall be punishable by the penalties provided for in Article 226-13 of the Criminal Code.

For Internet collection, the collection site is completely secure and the standards for managing survey access codes are strict. For companies that choose to use paper, the data entry is carried out by the managers, with strict respect for the confidentiality of the data collected.
Before the data is released, confidentiality is applied. For company data: no results are published for less than three companies or establishments. Similarly, a result will only be disclosed if no company or establishment contributes more than 85% of that result. Primary deletions correspond to boxes that do not meet the above criteria. Secondary secrecy removes other boxes so that the data cannot be retrieved by subtraction with the margins of the tables. Statistical confidentiality is defined in Act No. 51-711 of 7 June 1951.