1) At the Treaty of Paris of February 10, 1763, French territory on the North American continent was divided between the British and the *Spanish*. During the Napoleonic wars, France became Louisiana back from *Spain* at the Third Treaty of San Ildefonso. 2) "The term French Louisiana refers to two distinct regions: - first, to colonial French Louisiana, comprised of the massive, middle section of North America claimed by France; and, - second, to modern French Louisiana, which stretches across the southern extreme of the present-day state of Louisiana. Each term has been in use for many years: - Colonial French Louisiana (part of New France): Beginning in 1682 this region, known in French as la Louisiane française, functioned as an administrative district of New France. It extended from the Gulf of Mexico to the current Canadian border. France ceded the region to Spain and Britain in 1763, regained part by treaty in 1800, and sold it to the United States in 1803 through the Louisiana Purchase. - Modern French Louisiana: Greater New Orleans and the twenty-two parish cultural region known as Acadiana compose present-day French Louisiana. Although Cajun and Creole cultures dominate south Louisiana's cultural landscape, other important ethnic groups in the region include African-Americans, Native Americans, Isleños, German Coast settlers and various immigrant groups, including Vietnamese, Laotians, Filipinos and a growing number of Hispanics. In addition, some French Louisiana influences can be found in cities adjacent to the region, such as Alexandria and Baton Rouge." Source and further information: http://en.wikipedia.org/wiki/French_Louisiana 3) "Following the French defeat in the French and Indian War, the Treaty of Paris of February 10, 1763, divided French territory on the North American continent between the British and the Spanish. The sole exception was the islands of Saint Pierre and Miquelon off the Canadian coast, retained as a fishing outpost. The islands of Saint-Pierre and Miquelon were France's only remaining possessions north of the Caribbean. France was able to briefly regain some of their former possessions in North America from the Spanish in 1800, during the Napoleonic Era, under the Treaty of San Ildefonso. However, after his troops were defeated in Saint-Domingue (now Haiti), Napoleon abandoned plans for a North American empire and sold the entire Louisiana territory to the United States, a sale referred to as the Louisiana Purchase." Source and further information: http://en.wikipedia.org/wiki/French_colonization_of_the_Americas 4) "The Third Treaty of San Ildefonso (formally titled the Preliminary and Secret Treaty between the French Republic and His Catholic Majesty the King of Spain, Concerning the Aggrandizement of His Royal Highness the Infant Duke of Parma in Italy and the Retrocession of Louisiana) was a secretly negotiated treaty between France and Spain in which Spain returned the colonial territory of Louisiana to France. The treaty was concluded on October 1, 1800 between Louis Alexandre Berthier representing France and Don Mariano Luis de Urquijo for Spain. The treaty was negotiated under some duress, as Spain was under pressure from Napoleon. The terms of the treaty did not specify the boundaries of the territory being returned, which later became a point of contention between Spain and the United States after the Louisiana Purchase in 1803, in which France sold its territory to the United States. This treaty also affirmed the earlier Treaty of Alliance signed at San Ildefonso on August 19, 1796. That treaty is sometimes also referred to as the Treaty of San Ildefonso." Source and further information: http://en.wikipedia.org/wiki/Third_Treaty_of_San_Ildefonso

The British ceded the territory of Louisiana to the French as part of the peace negociations at the Treaty of Versailles 1783 (I am fuzzy on the year). Napoleon then sold it back to pay for His wars.