I've been here a couple of times and it probably the most amazing castle city I've ever seen. It really feels like you're in a fairytale. The inside of the city has been wonderfully preserved with little cobbled streets. If you're interested in Cathar history then this is a must see sight, especially the church, which has some interesting symbols if you know where to look. When you walk along the ramparts, you get great views of the surrounding countryside and the Pyrenees in the distance. The only issue I had with it was that in the summer it gets incredibly busy, making it hard to walk around. There are also the typical souvenir shops, but some of them are quite nice and not tacky. If you can, it is much better to visit outside of summer, as it's a lot quieter. It can get quite windy in Carcassonne, so if you visit in the winter make sure to dress warm. Entry to the castle is free and there is a good amount of parking, but you'll have to pay. Definitely worth a visit in the off-peak season.
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