How does the section letter shift work in France?

The section letter shift works in France as it works in the European structure: when the old Section J was split into two sections, the sections that followed moved one letter forward. Section J in NACE Rev. 2.1 covers publishing, broadcasting and content production and distribution activities. Telecommunication, computer programming, consulting, computing infrastructure and other information service activities are covered by Section K. The French nomenclature follows the European structure, so the same shift applies to the French section letters.

A heading that sat after the old Section J therefore carries a new letter under NAF 2025, even where its activities and its lower level numbers are unchanged. The letter changed. The content, for a pure renumbering, did not.

Why does the shift matter for French codes?

The shift matters because an APE code is read with its section letter as part of the identifier, and because datasets often store codes without the version. A code that carried one letter under NAF rev. 2 and carries the next letter under NAF 2025 can be misread as a different activity, or a code that looks unchanged can be misread as the same heading, depending on where the shift falls. The CSO in Ireland describes the Section J split as the most obvious structural change in NACE Rev. 2.1, and the same warning applies in France: the split is visible, but its effect on every later letter is easy to miss. A reader who compares French codes across the change should state the nomenclature version beside every code, and should check the section letter against the version in force for the period of the source.

Position	Old Section J area	New sections
At the split	Information and communication, one section	J content production and distribution, K telecommunication and information services
After the split	Each later section, one letter earlier	Each later section, one letter later, same activity area unless restructured

The table above describes the mechanism in general terms. It does not list French section titles, because French titles must be read on the INSEE website, and this guide does not assert them from a secondary summary.

How is a shifted heading distinguished from a restructured heading?

The correspondence row and the explanatory note together distinguish a shifted heading from a restructured heading. In a pure shift, the row is one to one, the lower level numbers are unchanged, and the note for the new heading matches the note for the old heading. In a restructure, the row shows movement, or the note shows added or removed content, or both. The section letter alone cannot make the distinction. A reader must therefore check the row and the note for the heading concerned, in the INSEE material, before concluding that a new letter means only a new address. The check is heading by heading. A general statement that letters shifted does not prove that any particular heading kept its content.

What should dataset users do?

Dataset users should record the version beside every French code, and should not join series across 1 January 2027 (FIXED) by letter alone. Series compiled under NAF rev. 2 and series compiled under NAF 2025 should be joined through the correspondence material and any comparable series that INSEE or Eurostat publishes, not by matching letters or digits. A series that follows a shifted section by its new letter, without checking the row and the note, will mix headings that moved with headings that only shifted. The result will look continuous and will be wrong. The correspondence material prevents that error, because it shows, heading by heading, whether content moved.

What does the shift not decide?

The shift does not decide the code for any specific unit, and it does not decide tax, licensing, funding or collective agreement questions. It is a change in how headings are addressed in the classification. The entry for a specific unit is in Sirene, and INSEE confirms it. A new letter does not create a new obligation, and an unchanged lower level number does not preserve an old obligation. The authorities applying their own rules own those questions. The classification remains statistical in character, as the EUR-Lex summary states for the European legislation.

Letters after the old Section J moved one step forward, a new letter alone proves only a new address, and the row and the note for each heading show whether its content moved as well. ”