Okay so I found that there is 3 problems here:
1 - The package is missing from the repositories (and maybe more)
2 - Trisquel relies on the version 2.x of the Users and Accounts package but
Gnome3 relies on the version 3.x. This is why nothing happens.
3 - There is no Home Folder on Gnome 3
Those 3 problems are only because of 1 issue.. The fact that the Desktop is
around the idea of the fallback version, and this is why installing another
DE (based on Gnome3 like Cinnamon or Gnome3) will give a lot a problems...
I will try to see how to solve this but I promise nothing.
