The Journal Officiel de la République Française, or JO, is a daily French government publication that lists all the new national laws and decrees, as well as senior government job vacancies, and legal notices such as changes of name and acquisition of French nationality (some publications with personal information require permission to access them).
Since 2016 it is only online at official legal information site Légifrance (you can consult it at legifrance.gouv.fr/initRechJO.do) Before that it had existed in both paper and online formats since 2004.
It is published by the Direction de l’information légale et administrative (Dila), a service of the Prime Minister’s office, every day apart from Mondays, except if the previous day was a bank holiday. Its offices are at rue Desaix in south-west Paris.
The most important aspect of the JO is that new laws are not operative until they have been published in it.
This is because laws must be made public if they are to apply. Unless the law in question mentions a later date, it applies from the day after publication. However, any articles in a law that mention the need for additional decrees to put them into practice do not apply until the decree has itself been published in the JO.
Another role of the JO is publicising parliamentary debates, but the full verbatim of these is hosted at the sites of the respective bodies at www.assemblee-nationale.fr (click Dans l’hémicycle > Comptes rendus des séances) or senat.fr (Travaux parlementaires > Comptes rendus des débats). The JO service also publishes information about non-profit-making associations.
Historically, new laws were announced by a town crier, known as tambour de ville (town drum) from the fact that he or she banged a drum. The first newspaper to carry official notices was then the Gazette de France, from 1762. The Journal Officiel dates from 1868 and has had the monopoly on publishing new laws since 1870.
It should not be confused with a bulletin officiel, which provides updates from certain ministries, of which the best-known is the Finance Ministry one, mostly about taxes. This was called Bulletin Officiel des Impôts (BOI) until 2012 and since then (more accurately but less snappy) Bulletin Officiel des Finances Publiques-Impôts (BOFiP-Impôts).