Staufen is the property of Swabia, and Swabia can decide what to do with it as it pleases. Metz has not yet been conquered or allocated to a house yet, but assuming it's given to Swabia, then the Swabian governors of Staufen and Metz decide how to develop the settlement.
EDIT - Basically cities and castles are the property of the Ducal House they belong to, and can't be touched by anyone but the governor.
Bookmarks