It is pretty centric and you can have a lot of nice options to eat here. Always make a reservation otherwise will be very difficult to get a table, on weekends it is completely filled with groups of friends or young families eating here.
It is a local market where people buy their goods but they opened various restaurants inside. The atmosphere is 100% local. It is centric, near Calle Princesa that goes straight ahead to Gran Via, so you can take a walk there after your lunch.
My favorite spots there are Tripea and Kitchen 154.