Every Azure account is bound to at least one Azure Directory. My Azure Directory was named "Répertoire par défaut" for ages. I didn't know how to rename it and I wasn't sure what would be the impact of that renaming. Turns out it's not as hard as I thought and there are no particular side effects.

Since I was a student I always had multiple Azure Subscriptions, Each of them had a different capabilities and amount of money included. It became such a waste of time that I decided to find a solution to tell the difference between each of them.