In 1803, General Charles Decaen was appointed Governor of Isle de France by Napoleon Bonaparte. The capital then became Port Napoleon while Mahébourg was named Port Impérial. From 1806 the British were deployed in the Indian Ocean and the powerful British fleet established a blockade around the islands. In 1809 they took Rodrigues, then Réunion in July 1810.
In August 1810, the English attempted to besiege Isle de France, attacking the south of the island from Bel Ombre, then from the south east at Vieux Grand Port. Despite the numerical superiority of their fleet, the Battle of Vieux Grand Port was a French victory, the only naval battle won by Napoleon.
The British retreated to Rodrigues Island and prepared a new offensive. On December 3, 1810, 70 ships and more than 10,000 men landed this time on Isle de France on the north coast, at Cap Malheureux. The British Army under the command of General John Abercrombie won and took over the island. The current Abercrombie Police Station is the historic site where General Decaen signed the Act of Surrender to Sir John Abercrombie. Îsle de France then took the name of Mauritius, Port Napoleon that of Port Louis and Port Impérial became Mahébourg.