Two buildings in one
From the moat the château is a defensive ring of granite towers. Through the gate it is a late-Gothic palace in pale tuffeau limestone, built for living rather than for holding out. The contrast is the whole point of the building.
The courtyard and the rampart walk are free. The museum inside — thirty-two rooms on the history of the city, including the slave trade — is the ticketed part.
Brittany, and why this matters here
The dukes ran an effectively independent state from here until the duchy was absorbed into France. Anne of Brittany, twice queen of France, came from this line.
Nantes is not in the modern administrative region of Brittany, and a good number of Nantais will tell you it should be. The château is where that argument is grounded.
What is next door
The cathedral is five minutes away, free, and holds the tomb of the last duke. Bouffay, the medieval quarter the bombing missed, is four minutes in the other direction.
Château des Ducs de Bretagne
Cathédrale Saint-Pierre-et-Saint-Paul
Quartier Bouffay