By the Treaty of San Ildefonpo ( 1801) Louisiana was ceded to France. The colonists were not formally notified of the transfer until the arrival in March 1803 of Pierre Laussat, the Colonial Prefect sent by Napoleon to take over the Colony. He was coldly received, for although New Orleans was preponderantly French, the townspeople were not enthusiastic about the change. The substitution of French assignats of fluctuating value for Spanish silver, the possibility of new laws affecting commerce, and the revolutionary policy that had bred the revolt at Santo Domingo were cause for alarm to a populace grown accustomed to peace under the Spanish. Laussat was considered a dangerous revolutionnaire by the royalists and émigrés, and so frightened were the Ursuline nuns of the emissary of an anti-Catholic government that most of them left for Havana in June, despite the assurance and pleadings of Laussat.
News of the sale of Louisiana to the United States ( April 30, 1803) arrived in August and placed Laussat in an embarrassing position. The great plans he had contemplated for the Colony during his régime were of no consequence, since his official capacity was now concerned merely with the taking over of Louisiana from Spain and the immediate cession of it to the United States.
The ceremony of transfer to France was fixed for November 3. By noon that day the principal part of the population of New Orleans had assembled in the Place d'Armes to wait in the rain while Salcedo, Governor of. Louisiana, the Marquis of Casa Calvo, Spanish Commissioner, and Laussat met in the Hôtel de Ville (Cabildo) to read the proclamation of transfer. Absolution from their oath of allegiance was granted to all Spaniards not wishing to retain their citizenship, and the keys to Fort St. Charles and Fort St. Louis were handed to Laussat on a silver plate. The official party then made its way to the square, where the Spanish flag was taken down and the French Tricolor raised in its stead.
Twenty days later transfer of the Colony to the United States took place. Claiborne, Wilkinson, and Laussat met at the Cabildo, and after conducting ceremonies similar to those of November 30 joined the crowd assembled in the Place d'Armes. After the American troops had arrived the ceremony of the interchange of flags was gone through. Although the Tricolor of France descended without a hitch, the American flag stuck and caused some difficulty in hoisting. A banquet of 450 places, started at three o'clock in the afternoon, was followed by a dance, which ended late the next morning.
New Orleans was as dissatisfied with the transfer to the United States as it had been with retrocession to France. The Creole element of the town, which outnumbered the American residents twelve to one, disliked Claiborne as governor because he knew little concerning their country, people, or language. He surrounded himself with Americans, and the number of them he put in office seemed to the Orleanians to be out of all proportion to their representation. The introduction of new customs, and particularly the use of English as the official language, outraged the town. Insurrectionary placards posted at night, and duels and clashes between Orleanians and Americans in the streets and in ballrooms, added to the bitter feeling, which culminated in a petition to Congress for admission to the Union and the right to elect a governor.