Just to clarify, there are several attractions at Carcassonne and two of them get mixed up in these reviews.
There is the restored Medieval walled city - called the Cité
Inside the Cité is the Château Comtal - the castle of the Medieval Viscounts of Carcassonne
The Castle is built against the interior city walls, so you can get to the walls (ramparts) both by the cité and the castle.
The part accessed from the cité is small (most of it is cordoned off) and there is precious little information provided, but it is free and interesting if you have a guide book or know about medieval castles.
The part accessed from the castle is more extensive. You pay for access, and this entitles you to a guided tour (in French unless you are very luck, in high season). You can also pay (more) for an audio guide in English.
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