Air raid shelter, Cr Dupré Saint-Maur, Bordeaux

Located within the grounds of the old SNCASO factory, which is now a Police fasility.
SNCASO (abbreviated from Société nationale des constructions aéronautiques du Sud-Ouest). In the late 1930's France started to build "passive defense" structures. shelters, mostly for children. All schools, hospitals, etc. Had shelters built. I presume then that factories had to have them.
Equipped with a gas-tight, zigzag-shaped (stepped) entrance door and a small water reserve, the underground shelter could accommodate around thirty people.

The entrance door.
In Germany there were many above-ground bomb shelters like this one, were officially called Winkeltürme (Winkel Towers) after their designer, architect Leo Winkel. Zossen, Germany.