4 December is the feast of Saint Barbara (in French: Sainte-Barbe)
She is "the patron saint of artillerymen. She is also traditionally the patron of armourers, military engineers, gunsmiths, miners and anyone else who worked with cannon and explosives. She is invoked against thunder and lightning and all accidents arising from explosions of gunpowder." https://en.wikipedia.org/wiki/Saint_Barbara
On a French warship, the Sainte-Barbe can refer to the powder magazine and/or the gun-room.
On old warships the powder magazine was surrounded by the bread-room to help keep the powder dry and also to protect it from canon balls.
In Provence, on the fourth of December, you are supposed to 'plant' grains of wheat (or sometimes lentils) in a dish on a piece of wet cotton. Tradition says that if it grows well you will be prosperous the next year. Quite a lot of people still do it even though most say that it hasn't worked for them