The Treaty of Paris (1783) didn't create the US and it wasn't done by the "international community" (whatever that means). It was a treaty between the 13 colonies, as then constituted under the Articles of Confederstion, and Great Britain in which GB acknowledged the United States (ie, the 13 colonies) to be free, sovereign and independent states.
Furthermore, the US as it is now did not come into existence until 1789, with the current Constitution, so the Treaty of Paris some 6 years earlier could not have had anything to do with it.
This "professor" is as dumb as a box of rocks.