Carcassonne is definitely worth a visit.
Maontclar itself does not consist of much… For culture you can go to Carcassonne and Lastours and Montsegur. For beaches you will nevertheless have to drive for over an hour. You will have to look for the nightlife. There are no restaurants in the direct
We did not experience the nightlife. Montclar itself is only small village but near to Carcasonne and that is great.