France signed the 1778 Treaty of Alliance with the United States during the American Revolution.
The treaty was signed in Paris on February 6, 1778, by representatives of King Louis XVI and the Second Continental Congress. It created a defensive military alliance against Great Britain and formalized French recognition and support for the American cause. A separate Treaty of Amity and Commerce was signed the same day.
France supplied weapons, money, troops, and naval power. French assistance became especially important in the war’s later stages, including the naval operations surrounding the 1781 siege at Yorktown. The alliance followed the American victory at Saratoga, which persuaded French leaders that the rebellion had a realistic chance of success.
Spain entered the war against Britain in 1779, but it did not sign the same alliance treaty with the United States. The Dutch Republic also became involved later. The French-American alliance was eventually strained by the French Revolutionary Wars and was formally ended by the Convention of 1800.