Title: Louisiana Purchase
Content:  the Louisiana Purchase Treaty on April 30, 1803, at the Hôtel Tubeuf in Paris. The signers were Robert Livingston, James Monroe, and François Barbé-Marbois. After the signing Livingston famously stated, "We have lived long, but this is the noblest work of our whole lives... From this day the United States take their place among the powers of the first rank." On July 4, 1803, the treaty was announced, but the documents did not arrive in Washington, D.C. until July 14. The Louisiana Territory was vast, stretching from the Gulf of Mexico in the south to Rupert's Land in the north, and from the Mississippi River in the east to 
Title: Louis-André Pichon
Content:  France had then secretly acquired Louisiana, and diplomat Robert Livingston negotiated the Louisiana Purchase as a whole, in 1803. On 1 October 1802, Louis-Andre Pichon wrote to the U.S. government to reassure them, when the Spanish intendant of New Orleans decided to terminate the offloading of U.S. merchants in the port, which was French property, following a secret treaty in 1800.
Title: Aboriginal title in Louisiana
Content:  In 1803, the United States purchased France's claim to Louisiana in the Louisiana Purchase. The 1804 act forming the Louisiana Territory declared that any Spanish grants during the disputed period, “under whatsoever authority transacted, or pretended,” were “from the beginning, null, void, and of no effect in law or equity."
Title: Louisiana (New France)
Content:  During the French Revolution, Louisiana was agitated under Spanish control: certain French-speaking colonists sent petitions to the metropolis and the slaves attempted revolts in 1791 and 1795. The Third Treaty of San Ildefonso, signed in secrecy on October 1, 1800, envisaged the transfer of Western Louisiana as well as New Orleans to France in exchange for the Duchy of Parma. The transfer was confirmed by the Treaty of Aranjuez signed on March 21, 1801. However, Napoleon Bonaparte soon decided not to keep the immense territory. The army he sent to take possession of the colony was first required to put down a revolution in Saint-Domingue (now Haiti); its failure to do so, and the rupture of the Treaty of Amiens with the United Kingdom, prompted him to decide to sell Louisiana to the newly founded United States. This was done on April 30, 1803 for the sum of 80 million francs (15 million dollars). American sovereignty was established on December 20, 1803.
Title: Louisiana Purchase Historic State Park
Content:  On April 30, 1803, negotiators for the United States and the First French Empire, signed the Louisiana Purchase agreement, by which the United States acquired 830000 sqmi of land west of the Mississippi River, doubling its size. President Thomas Jefferson commissioned the Lewis and Clark Expedition, which traveled west along the Missouri and associated rivers, eventually reaching the Pacific Coast, from 1804 to 1806. President James Monroe ordered a survey of the territory in 1815, in order to permit the orderly award of land in the territory to military veterans of the War of 1812. Prospect K. Robbins and Joseph C. Brown were commissioned to 
Title: Louisiana Purchase
Content:  The Louisiana Purchase (Vente de la Louisiane) was the acquisition of the territory of Louisiana by the United States from Napoleonic France in 1803. In return for fifteen million dollars, or approximately eighteen dollars per square mile, the United States nominally acquired a total of 828000 sqmi. However, France only controlled a small fraction of this area, most of it inhabited by Native Americans; for the majority of the area, what the United States bought was the "preemptive" right to obtain "Indian" lands by treaty or by conquest, to the exclusion of other colonial powers. The total cost of all subsequent treaties and financial settlements over the land has been estimated to 
Title: War of the Third Coalition
Content:  the First Consul to abandon his plans to rebuild France's New World empire. Without sufficient revenues from sugar colonies in the Caribbean, the vast territory of Louisiana in North America had little value to him. Though Spain had not yet completed the transfer of Louisiana to France per the Third Treaty of San Ildefonso, a war between France and Britain was imminent. Out of anger against Spain and having the unique opportunity to sell something that was useless and not truly his yet, Bonaparte decided to sell the entire territory to the United States for a sum total 68 million francs ($15 million). The Louisiana Purchase Treaty was signed on 30 April 1803. 
Title: Louisiana Rebellion of 1768
Content:  Ildefonso. However, Spanish officials continued to administer the colony. In April 1803, Napoleon sold La Louisiane to the United States in the Louisiana Purchase, in exchange for money and the cancellation of French debts. Late in 1803 and in the spring of 1804, both of these transfers were formalized back-to-back, with the French flag being raised temporarily in New Orleans and again later in St. Louis. Then the French flag was lowered and the American flag raised. The 1804 ceremony in St. Louis, was called Three Flags Day. Elements of French law still remain in the state of Louisiana.
Title: Louisiana Purchase
Content:   France turned over New Orleans, the historic colonial capital, on December 20, 1803, at the Cabildo, with a flag-raising ceremony in the Plaza de Armas, now Jackson Square. Just three weeks earlier, on November 30, 1803, Spanish officials had formally conveyed the colonial lands and their administration to France. On March 9 and 10, 1804, another ceremony, commemorated as Three Flags Day, was conducted in St. Louis, to transfer ownership of Upper Louisiana from Spain to France, and then from France to the United States. From March 10 to September 30, 1804, Upper Louisiana was supervised as a military district, under its first civil commandant, Amos Stoddard, who was appointed by the War Department. Effective October 1, 1804, the purchased territory was organized into the Territory of Orleans (most of which would become the state of Louisiana) and the District of Louisiana, which was temporarily under control of the governor and judicial system of the Indiana Territory. The following year, the District of Louisiana was renamed the Territory of Louisiana. New Orleans was the administrative capital of the Orleans Territory, and St. Louis was the capital of the Louisiana Territory.
Title: History of Montana
Content:   On April 30, 1803, the Louisiana Purchase Treaty was signed by representatives of the U.S. at Paris, France. The United States Senate ratified the treaty on October 20 and President Thomas Jefferson announced the treaty to the American people on July 4, 1803. The area covered by the purchase included much of the present-day United States between the Continental Divide and the Mississippi River, encompassing the Great Plains including part of what is now Montana, particularly the Missouri River drainage. The rights to the Louisiana Purchase territory cost the U.S. $15 million, which came out to an average of 3 cents an acre. On March 10, 1804, a formal ceremony was conducted in St. Louis, Missouri, to transfer ownership of the territory from France to the United States of America. The lands of present-day Montana were practically unknown and too distant from the seats of power for this political boundary change to have much impact upon them, but the Louisiana Purchase would prove a sea-change for the area.

Question: where was the louisiana purchase signed in 1803?
Answer: Paris.