The most expensive luxury residences in Spain can be found in the Balearic Islands and Madrid.
This is evidenced in Hiscox’s I Report on the Luxury Housing Market in Spain, which includes, among other data, prices per square metre by city and region.
According to this report, Formentera has the most expensive luxury properties with a price per square metre of €9,383, followed by Recoletos (Madrid) at €9,000/m2, Portals Nous in Calvià (Mallorca) at 8,319 €/m2, Castellana (Madrid) at €7,956/m2, and Costa d’en Blanes in Calvià (Mallorca) at €7,839/m2.