France signed the 1778 Treaty of Alliance with the United States.
The treaty was signed in Paris on February 6, 1778, by American commissioners Benjamin Franklin, Arthur Lee, and Silas Deane and French representative Conrad Alexandre Gérard. It created a defensive military alliance during the American Revolutionary War.
France had already been supplying the American cause secretly, but the American victory at Saratoga in 1777 helped convince French leaders that the rebellion had a realistic chance of success. The alliance brought open French military, naval, and financial support against Britain.
French assistance was especially important at Yorktown, where French troops and warships helped prevent Cornwallis's escape or reinforcement. Spain later entered the war against Britain as a French ally, and the Dutch Republic also became a British enemy, but neither signed this specific Franco-American treaty.