Accord-cadre à marchés subséquents relatif à la réalisation de travaux de voirie et réseaux divers et aménagements extérieurs sur les sites de la base de défense de Brest-Lorient (hors Île Longue et Guenvenez)

A Concessio ID is a 12-character canonical identifier for an infrastructure concession. The format is CC-AA-S-NNNNNN-K — country, asset class, structure, sequence, and a Luhn check digit. The check digit protects against typos and fabricated IDs.

Concessio IDs are stable for the life of the concession. They do not change if the asset is renamed, sold, or restructured. Cite them in filings, press releases, research reports, and contracts.