(Bloomberg) -- Some of Europe’s biggest cities, including London and Paris, will have a shortfall of 1.2 million apartments by 2030, according to a study of nine metropolises by the German Institute for Economic Research for real estate developer Wiener Komfortwohnungen. The U.K. capital accounts for the biggest share: it faces a gap of almost 355,000, which would be an 11% increase from the current level.