Statistical confidentiality is defined by Act No. 51-711 of 7 June 1951 on the obligation, coordination and confidentiality of statistics. It prohibits the communication of individual data or data likely to allow the identification of persons, resulting from processing for statistical purposes, whether they were initially obtained by means of a statistical survey or from databases. However, exemptions may be granted, on the opinion of the Statistical Confidentiality Committee, in response to requests of public interest whose purpose is statistical or related to scientific or historical research.
Statistical confidentiality excludes that data collected for statistical purposes can be used or re-used for decision-making purposes towards the persons concerned - both natural and legal persons. In particular, it strictly excludes any use or re-use of such data for tax control or economic repression.
Any person accessing data collected for statistical purposes (interviewers, census takers, statisticians, authorised applicants) is subject to statistical confidentiality. Like all civil servants and employees of the public service, the employees of the official statistical system are also subject to the obligations of professional secrecy and discretion (Article 26 of Act No. 83-634 of 13 July 1983 on the rights and obligations of civil servants), which apply to the files and information of which they have knowledge in the course of their activities.
Application to the dissemination of statistical information
Statistical confidentiality excludes, as a matter of principle, the dissemination of data that would allow the identification of the persons concerned, whether natural or legal persons. This obligation limits the detail of the information available for dissemination. It is expressed more particularly with regard to the dissemination of data concerning natural persons (Article L312-1-2 of the Code of Relations between the Public and the Administration).
Rules facilitating the application of this principle are nevertheless admitted in practice. They may depend on the type of sources, the nature of the data and the entities concerned (individuals or businesses).
For individuals, rules are thus set specifically for population censuses.
For businesses, in the general case, no result is published if it concerns less than three enterprises, or if a single enterprise represents 85% or more of its value. However, it is admitted that the dissemination of lists extracted from the register of enterprises or establishments may mention the economic activity, a class of employees and a turnover bracket.