Napoleon III is the mastermind who gradually decided to conquer the country of Vietnam due to its vast product of minerals such as gold, bronze and other precious minerals. Rigault de Genouilly is a French Conqueror who also ordered to attack Vietnam specifically in the City of Da Nang and turn it into a military base. Since then, he decided to attack Saigon (the capital of Vietnam) to gain more progress.
Hope it Helps =)
------Domini-----