Flats for €60 Million Show Monaco’s Dirty Money Headache

Standing on the windswept balcony of the expansive apartment in Monaco’s Mareterra development feels a little like being on a superyacht heading out to sea. The unobstructed view of the Mediterranean stretches to the horizon, the pale ash floors evoke a ship’s deck, and fresh breezes keep things cool even on the hottest summer days. The other thing the flat shares with a floating luxury palace: its price. Listed at more than €60 million ($70 million), the three-bedroom home costs more than many billionaires might spend on a sumptuous schooner or cruiser.

Those prices haven’t stopped the world’s ultrawealthy from ...