There were several people credited with writing the Treaty of Paris, both Americans and British representatives.

There were actually a few people who wrote The Treaty of Paris: three American representatives – Benjamin Franklin, John Adams, and John Jay – along with negotiators from Great Britain, in particular a man named David Hartley.
Written in 1783, the Treaty of Paris was a peace treaty following the Revolutionary War. Its terms outlined American independence from Britain, as well as the American borders (allowing for Western expansion); it also stated that the Americans promised to respect loyalists within their borders and to allow British merchants to collect money still owed them by those on American soil.
The treaty came into being after the British lost to the Americans at the Battle of Yorktown. Exhausted and defeated, the British chose this point in time to offer a negotiation, and the three American representatives were sent to Paris accordingly.
The three Americans met in Paris with the British negotiators, including David Hartley, and together the group came up with the terms of the treaty. Named for the city in which it was signed, the treaty bears the names of all three Americans as well as Hartley, all signed in alphabetical order.
The Treaty of Paris not only delineated the terms of the relationship between America and Great Britain; it also officially indicated America’s independence as a country, and it brought an end to the Revolutionary War.