Final answer:
The Battle of Fort William Henry was the event in which the British and French forces engaged, resulting in a massacre and the loss of French territory. After the Treaty of Paris in 1763, France retained two territories: Saint Pierre and Miquelon and Guadeloupe and Martinique.
Step-by-step explanation:
The battle between the British and French forces that was considered a massacre, leading to the loss of French territory in North America, was the Battle of Fort William Henry. In 1757, Britain suffered a defeat with the fall of Fort William Henry. After this event, the Treaty of Paris was signed in 1763, and as a result, France lost all North American possessions except for two territories. The two territories that remained part of the French Empire after the Treaty of Paris were Saint Pierre and Miquelon and Guadeloupe and Martinique, with the former being correct in this context.