It was no longer the largest city in Europe; London passed it in population in about 1700, but it was still growing at a rapid rate, due largely to migration from the Paris basin and from the north and east of France. The center of the city became more and more crowded; building lots became smaller and buildings taller, up to four, five and even six stories. In 1784, the height of buildings was finally limited to nine toises, or about eighteen meters.[71]