Franco - American alliance The Franco - American alliance refers to the 1778 alliance between Louis XVI ' s France and the United States during the American Revolutionary War . Formalized in the 1778 Treaty of Alliance , it was a military pact in which the French provided many supplies for the Americans . The Netherlands and Spain later joined as allies of France ; Britain had no allies . The French alliance was possible once the Americans captured a British invasion army at Saratoga in October 1777 , demonstrating the viability of the American cause . The alliance became controversial after 1793 when Britain and France again went to war and the U . S . declared itself neutral . Relations between France and the United States worsened as the latter became closer to Britain in the Jay Treaty of 1795 , leading to an undeclared Quasi War . The alliance was defunct by 1794 and formally ended in 1800 . Background . France had been left deeply alarmed by the British success in the seven Years War which they feared gave the British naval superiority . From 1763 both France , and their allies Spain , began to rebuild their navies and prepare for a future war in which they would construct an alliance to overwhelm and invade Britain . As Britain ' s troubles with its American colonies intensified during the 1760s and eventually led to open rebellion in 1775 , France began to anticipate the American rebels joining such an alliance . In September 1775 the Continental Congress described foreign assistance as " undoubtedly attainable " and began to seek supplies and assistance from European powers hostile to Britain . The French leadership sought the " humiliation of England " and began giving covert aid to the rebels . The American declaration of independence was advocated by some as necessary in order to secure European support against Britain . Silas Deane , an American envoy in Paris , proposed a major anti - British alliance and French invasions of Hanover and Portugal which were both British allies . The alliance was promoted in the United States by Thomas Jefferson , a Francophile . Based on the Model Treaty of 1776 , Jefferson encouraged the role of France as an economic and military partner to the United States , in order to weaken British influence . In 1776 , Latouche Tréville transferred ammunition from France to the United States of America . Numerous French supplies as well as guns of the de Valliere type were used in the American War of Independence , especially the smaller 4 - pounder field guns . The guns were shipped from France , and the field carriages provided for in the US . These guns played an important role in such battles as the Battle of Saratoga , and the Siege of Yorktown . George Washington wrote about the supplies and guns in a letter to General Heath on 2 May 1777 : On 13 June 1777 , the Marquis de Lafayette reached America and joined George Washington in the Continental Army as Major General . He participated to the Battle of Brandywine where he was wounded , and later served at the Battle of Rhode Island . Lafayette would later return to France during the war in order to advocate more support for the American cause . Treaty of Alliance . The alliance was formally negotiated by Benjamin Franklin and the 1778 Treaty of Alliance was signed on February 6 , 1778 after the American victory at the Battle of Saratoga , under the designation of " Franco - American Treaty of Amity and Commerce " . The treaty gave open support from the French Army , Navy and Treasury , and spelled that the United States was obligated to guaranty " from the present time and forever , against all other powers ( . . . ) the present Possessions of the Crown of France in America " , in exchange for a promise not to increase French possessions anymore in America . Operations . The combined strength of the Americans and the French virtually guaranteed victory against Great Britain . France successfully supported the American War of Independence , managing to expel the British and obtain recognition of American independence through the intervention of Rochambeau , La Fayette , de Grasse , and Suffren . European front . Naval conflict started in European waters with the First Battle of Ushant in July 1778 , and continued with the attempted invasion of Britain by the Armada of 1779 . 1st American campaign . In the summer of 1778 , French Admiral d ' Estaing arrived with a fleet and infantry reinforcements for the war with a fleet of twelve ships of the line and fourteen frigate s . After declining to attack Richard Howe ' s inferior British force outside New York , the French fleet sailed to Rhode Island where they were to take part in an attack on Newport . On 6 July 1779 , he successfully fought the Battle of Grenada against Admiral Byron , but failed at the September 1779 Siege of Savannah before returning to France . Actions continued in April 1780 with Guichen against Admiral Rodney in the Battle of Martinique . 2nd American campaign . In 1780 , Rochambeau arrived with a fleet and 6 , 000 French troops to join the Continental army , under George Washington , in the " Expédition Particulière " , landing in Newport , Rhode Island , on 10 July . In the Ohio valley , French Americans would also combine with Indian troops , as in the Battle of Kekionga in 1780 under Augustin de La Balme . The French Navy played a decisive role in supporting the American side , as American forces could hardly resist the powerful British Navy . The French under de Grasse managed to defeat a British fleet at the Battle of the Chesapeake in 1781 , thus ensuring that the Franco - American ground forces would win the ongoing Siege of Yorktown , the last major land battle of the Revolutionary War . The British surrendered to American and French forces at Yorktown in 1781 . France continued to fight against the British in the 1782 Antilles War . Campaign in India . France further supported the war effort against Great Britain by attacking British possessions in India . In 1782 , Louis XVI sealed an alliance with the Peshwa Madhu Rao Narayan . Suffren became the ally of Hyder Ali in the Second Anglo - Mysore War against British rule in India , in 1782 – 1783 , fighting the British fleet on the coasts of India and Ceylon . Between February 1782 until June 1783 , Suffren fought the English admiral Sir Edward Hughes , and collaborated with the rulers of Mysore . Suffren fought in the Battle of Sadras on February 17 , 1782 , the Battle of Providien on April 12 near Trincomalee , the Battle of Negapatam ( 1782 ) on July 6 off Cuddalore , after which Suffren seized upon the anchorage of Trincomalee compelling the small British garrison to surrender . An army of 3 , 000 French soldiers collaborated with Hyder Ali to capture Cuddalore . Finally the Battle of Trincomalee took place near that port on September 3 . These battles can be seen as the last battles of the Franco - British conflict that encompassed the American War of Independence , and would cease in 1783 with the signature of the 1783 peace treaty . Aftermath . Finally , the Treaty of Paris was signed on 3 September 1783 , recognizing American independence and the end of hostilities . The 1778 Treaty of Alliance , promising the defense of French territory in the American continent , failed to be observed by the United States as soon as 1793 , when France entered in conflict with Great Britain in the Caribbean . All the U . S . could do was maintain neutrality , but this neutrality was so negative as to forbid the French the right to equip and arm privateers in American ports , or the right to dispose of French prizes in the United States . These reluctances in effect marked the end of the alliance . As the United States entered into a treaty of commerce with Great Britain in 1794 , France started to raid American shipping , seizing 316 ships in 1796 . In 1796 , the disillusioned Minister Pierre Adet explained : " Jefferson ( . . . ) is American , and as such , he cannot sincerely be our friend . An American is the born enemy of all the European peoples " , and in 1798 , the XYZ Affair considerably worsened Franco - American relations . The events led to the Quasi - War ( 1798 – 1800 ) between France and the United States , with actual naval encounters taking place between the two powers , with the encounter between USS " Constellation " and French ship " L ' Insurgente " on 9 February 1799 off Nevis Island , and USS " Constellation " and " La Vengeance " in February 1800 off Guadeloupe . An agreement followed , in which the United States agreed to pay 20 million dollars in compensation , and France agreed to give up its claims to the 1778 Treaty . Britain would also attempt to interfere with American trade and shipping , starting with the Orders in Council in 1807 , which forbade trade with France by Britain , her allies , and any neutral nation , which meant the United States . The US protested that this act was illegal under international law , and this act was a contributory factor to the enmity between the US and Britain which caused the War of 1812 . Historical perspectives . Many historians originally agreed that the American victory over the British at Saratoga , New York was the deciding factor in the formation of the alliance . However , in recent decades , historians have begun to rethink the victory ' s contribution to the formation of the alliance . These historians see the alliance as an inevitable result of individual governmental interests . In the wake of the Seven Years ' War , the American Revolution began across the Atlantic . Britain ' s victory against France and its allies in the war made the French feel vulnerable to British power . The French saw the American Revolution as a way to strengthen itself and cripple the British Empire . At the beginning , the French helped fuel the American war effort but never came out as an official ally on the side of the Americans . American envoys to France , namely Silas Deane , feared that the French would never join the war . They were so fearful , they thought of telling the French that if the French didn ' t sufficiently support the war effort , the Americans would begin peace talks with Britain . Charles Gravier , comte de Vergennes appeared ready to offer official treaty negotiations , as long as the Americans promised to remain independent . Because they had consistently maintained the nonnegotiability of independence , Vergennes ’ s demand proved that their strategy to threaten reunion with Britain influenced France ’ s thinking . It also demonstrates that the victory at Saratoga played little role in the calculations of American , French , and British diplomats . Indeed , two more months of diplomacy would pass before the signing of the Franco - American treaty .