During the American Revolutionary War (American War of Independence; 1775–1783), France recognized and allied itself with the United States in 1778, declared war on Great Britain, and sent its armies and navy to fight Britain while providing money and matériel to arm the new republic. French intervention made a decisive contribution to the U.S. victory in the war. Motivated by a long-term rivalry with Britain and by revenge for its territorial losses during the French and Indian War, France began secretly sending supplies in 1775. Spain and the Netherlands joined France, making it a global war in which the British had no major allies. France obtained its revenge, but materially it gained little and was left with over 1 billion livres in debts.
I probably misspelled some stuff here or there, but it beats being slow :)