The population of Paris had doubled since 1815, with no increase in its area. To accommodate the growing population and those who would be forced from the centre by the new boulevards and squares Napoleon III planned to build, he issued a decree annexing eleven surrounding communes, and increasing the number of arrondissements from twelve to twenty, which enlarged the city to its modern boundaries.
The population of Paris had doubled since 1815, with no increase in its area To accommodate the growing population and those who would be forced from the centre by the new boulevards and squares Napoleon III planned to build, he issued a decree annexing eleven surrounding communes and increasing the number of arrondissements from twelve to twenty, which enlarged the city to its modern boundaries.