The Charter of 1815, signed on 22 April 1815, was the French constitution prepared by Benjamin Constant at the request of Napoleon I when he returned from exile on Elba. Officially named the Additional Act to the Constitutions of the Empire, the document extensively amended the previous Napoleonic Constitutions. The Additional Act reframed the Napoleonic constitution into something more along the lines of the Bourbon Restoration's Charter of 1814 of Louis XVIII, while otherwise ignoring the Bourbon charter's existence. It was very liberal in spirit, and gave the French people rights which had previously been unknown to them, such as the right to elect the mayor in communes of less than 5,000 in population. Napoleon treated it as a mere continuation of the previous constitutions, and it therefore took the form of an ordinary legislative act "additional to the constitutions of the Empire".