Final answer:
Approximately 20,000 French lives were lost during the construction of the Panama Canal.
Step-by-step explanation:
The construction of the Panama Canal resulted in the loss of approximately 20,000 lives among the French workers. Despite their experience in building the Suez Canal, the harsh tropical climate and prevalent diseases such as malaria and yellow fever proved to be major challenges for the French workers, leading to such a significant loss of life.