Short answers, pulled from the story.
The Treaty of Versailles 1768 transferred sovereignty over Corsica from the Republic of Genoa to France. Representatives from the Republic of Genoa signed an agreement with France on the 15th of May 1768 at Versailles. This deal allowed Genoa to sell the island to France in exchange for debt relief.
Diplomatic talks concluded on the 15th of May 1768 at Versailles. The signing marked the end of centuries of Genoese rule and began a new era for the Mediterranean region. No other power intervened during these negotiations.
The Republic of Genoa faced ruin in the mid-1700s with an empty treasury and mounting debts. They needed money to repay their debts and had no option but to pledge Corsica to France. The financial collapse left Genoa with no chance to ever repay its debts otherwise.
Pasquale Paoli led the movement for independence in the mid-1700s and founded the Corsican Republic in 1755. His government organized a structured resistance against foreign powers after Genoa asked France to send troops to the island in 1764. Theodore von Neuhof briefly became King of Corsica in 1736 before this period.
France began its conquest of Corsica in September 1768 and fighting intensified over the following months. The decisive Battle of Ponte Novu took place in 1769, giving France full military control of the island. The war ended with French dominance established across the entire island about one year from invasion to total victory.