CEDEX — courrier d'entreprise à distribution exceptionnelle — is La Poste's service for organisations that receive a large volume of post, which is sorted to them under a code of their own instead of being carried to their street address; the envelope writes that code where the postcode goes and CEDEX after the town: 75384 PARIS CEDEX 08.
What Spaw answers
address_type reads bulk_mail. In France it is read from CEDEX and AUTORISATION anywhere in a line and from CS and TSA at the start of one followed by a number; the same type covers the Antwoordnummer reply numbers of the Dutch and Belgian postal services and Sweden's Svarspost and Frisvar. A CS or TSA line — CS 70001, TSA 70011 — lands in po_box while is_po_box stays false; CEDEX itself stays on the town line as La Poste writes it (75384 PARIS CEDEX 08), so po_box stays null and the street stays in the answer and in formatted. Either way the bulk_mail risk weight is +20: an organisation's mailroom is a real delivery point, but it is nobody's front door.
The postcode is checked like any other. A CEDEX code is almost always five digits of its own: in the GeoNames file of 16 September 2026, 14,332 French codes carry CEDEX and four of them are also a town's ordinary code. France's postcode directory lists these codes under their five digits, with the town as the envelope writes it — Paris CEDEX 08 — among the code's places, so postcode_status reads live and the town written with CEDEX matches. France's directory is complete, so a CEDEX code it does not list answers postcode_not_found.
What it is not
A CEDEX or a reply number is not a box rented by a person and not a mail drop: it is an organisation's own arrangement with its postal service, and the post reaches the organisation it names. The answer says so about the address and nothing about anybody who works there.