Answer :
France was a key European ally of the Patriots. In February of 1778, France decided to declare a war on Britain, and this resulted in France sending money, troops and equipment to the Patriots.
One of the most important European allies of the Patriots was the French. The French decided to help the Patriots (aka American colonists fighting against the British) after the Battle of Saratoga. This decisive battle ensured the French that the colonists had a legitimate chance of defeating the British.
Along with this, the French were eager to help the American colonists due to their tense relationship with the British. The British defeated France in the French and Indian War, causing the French to loss a significant amount of land in the North American continent.
To help the Patriots, the French sent money, resources, and individuals (like Marquis De Lafayette) to help organize and supply the Patriot troops.