The Bombardment of Đà Nẵng (25 April 1847) was a naval incident that took place during the short reign of the Vietnamese emperor Thieu Tri (1841–47), which saw a considerable worsening of relations between France and Vietnam. The French warships Gloire and Victorieuse, which had been sent to Đà Nẵng (then called Tourane) to negotiate for the release of two French Catholic missionaries, were attacked without warning by several Vietnamese vessels. The two French ships fought back, sinking four Vietnamese corvettes, badly damaging a fifth, and inflicting just under 1,200 casualties on the Vietnamese. In response to this and other provocations, the French eventually decided to intervene actively in Vietnam, and a decade later launched the Cochinchina campaign (1858–62), which inaugurated the period of French colonial rule in Vietnam.
French naval captains in the Far East were given instructions to intercede with the Vietnamese authorities when such cases occurred. On two occasions they intervened with considerable success. On 25 February 1843 capitaine de frégate Favin-Lévêque, captain of the French warship Héroine, anchored off Danang to intercede for the release of five missionaries detained at Hue for two years. After long and frustrating negotiations, the five missionaries were released. In 1845 the French corvette Alcmène (capitaine de frégate Fornier-Duplan) went to Danang to ask for the release of Dominique Lefèbvre, the French vicar apostolic of Lower Cochinchina, who was being held prisoner at Hue. Again, the Vietnamese acceded to the French request, and Lefèbvre was released.
Cécille sent the 54-gun frigate Gloire (capitaine de vaisseau Augustin de Lapierre) and the 24-gun corvette Victorieuse (capitaine de frégate Charles Rigault de Genouilly) to Da Nang, with instructions to negotiate for the liberation of the two imprisoned French missionaries and to seek a commitment from the Vietnamese authorities to allow freedom of worship for Catholics in Vietnam. On this occasion, probably because the Vietnamese considered Lefèbvre's return to Vietnam a deliberate provocation by the French, the negotiations failed. Discussions dragged on without result, and on April 25, 1847 six Vietnamese corvettes attacked the two French ships in Da Nang harbour. In the brief action that followed the French sank four Vietnamese corvettes and disabled a fifth, and inflicted nearly 1,200 casualties on the outclassed Vietnamese sailors.
The classic French sources state that the Vietnamese prolonged the negotiations to win time to assemble a fleet, and that the two French ships were attacked without warning. Colonel Alfred Thomazi, the historian of the French conquest of Indochina, gave the following description of the battle in Da Nang harbour:
Capitaine de vaisseau de Lapierre sent the frigate Victorieuse to Tourane with Commandant Rigault de Genouilly, to try to obtain an agreement that Christianity would be tolerated in Annam as it was in China, coming in person aboard Gloire to join him a little later. The negotiations began in March 1847. But gradually the Annamese war fleet, consisting of five corvettes with covered batteries, several bricks and a large number of junks, gathered in the bay, and one morning, without prior warning, attacked the French vessels. These, as their armament was far superior, had little difficulty in destroying the entire enemy fleet, but they had to get underway thereafter, abandoning the Christians to the vengeance of their persecutors.
In fact, Lefèbvre was released by the Vietnamese authorities, either before or shortly after the battle (the sources differ).
Harassment of the Christians eventually provided France with a pretext for attacking Vietnam. The tension built up gradually. During the 1840s, the persecution or harassment of Catholic missionaries in Vietnam by the emperors Minh Mang and Thieu Tri evoked only sporadic and unofficial French reprisals, such as that taken by de Lapierre and Rigault de Genouilly in 1847. In 1857, however, the execution of two Spanish Catholic missionaries by the emperor Tu Duc led directly to French intervention in Vietnam. In September 1858 a joint French and Spanish naval expedition landed at Da Nang. Its commander was Admiral Charles Rigault de Genouilly, one of the two French naval captains involved in the 1847 incident. The resultant Cochinchina campaign inaugurated the era of French colonial rule in Vietnam.