The main commandpost of V. Marine Flak Brigade at St Marc was housed in a Fl 250, a so called "Flakgruppenkommandostand". The Flak batteries were manned by four Marine Flakabteilungen (Navy AA-battalions):
-- 703, La Vecquerie, 
-- 705, Montoir de Bretagne, 
-- 809, St Brévin,
-- 820, St Nazaire city, at the school in St Louis.

The light AA battalion 820 had small caliber guns and were spread out over the entire area. Each other heavy battalion had a searchlight battery. Searchlights were placed at a distance of approx 3 km from the main batteries.
The datasheet gives a review on organisation, armament, location and codenames.
A total of 72 anti-aircraftguns with a caliber of 10,5 or 12,8 cm were placed in the Festung St Nazaire.