Realising that the French garrison at
Tourane could achieve nothing useful, Rigault de Genouilly decided to strike elsewhere against the Vietnamese. He considered and rejected the possibility of an expedition to Tonkin, and in January 1859 proposed to the navy ministry an expedition against Saigon in Cochinchina, a city of considerable strategic significance as a source of food for the Vietnamese army. The expedition was approved, and on 2 February, leaving
capitaine de vaisseau Thoyon at
Tourane with a small French garrison and two gunboats, Rigault de Genouilly sailed south for Saigon. His naval force consisted of the corvettes
Phlégéton and
Primauguet, the gunboats
Alarme,
Avalanche and
Dragonne, the Spanish despatch vessel
El Cano and the transports
Saône,
Durance and
Meurthe. Rigault de Genouilly halted for five days in Cam Ranh Bay for four supply ships to join him with food for the expedition. On 9 February, he again got underway. On 10 February, the allied flotilla bombarded the forts that defended the interior harbour of
Cape Saint-Jacques and soon reduced their cannon to silence. The landing companies, a mixed force of French and Spanish soldiers under the command of
capitaine de vaisseau Reynaud, then went ashore and stormed the forts. On 11 February, the five-day voyage upriver began. The transports and the baggage were left at Cap Saint-Jacques. The gunboat
Dragonne scouted ahead, followed by the two other gunboats, the two corvettes and the Spanish despatch vessel. Three companies of marine infantry and two Spanish companies, 2,000 men in all, were distributed among the vessels which towed the launches of the naval force. The allied flotilla advanced cautiously as the currents were unknown, and anchored each night in the river. During their passage, the French and Spanish vessels halted to reduced six riverside forts, and squads of engineers under the command of
capitaine de génie Gallimard were put ashore to burn the wooden stockades that linked the forts. The Vietnamese defended themselves vigorously:
Dragonne was hit with three cannonballs, and
Avalanche by seven. The invaders took care to ensure that the river could not be closed behind them. After each fort was taken their cannons were either spiked or taken aboard the ships. , built and modeled after the French Vauban fortresses in 1790 On the evening of 15 February, the naval division (which had been joined in the river by the despatch vessel
Prégent) arrived in view of the two forts built by
Gia Long's French engineers, which defended Saigon from the south. During the night two armed launches were sent forward to destroy a barrage made of boats lashed together and filled with explosives. At dawn on 16 February
Phlégéton,
Primauguet,
Alarme and
Avalanche anchored 800 metres from the forts. The channel was so narrow that Admiral Charner, on
Phlégéton's bridge, was able to shout his orders to the captains of the other vessels.
Prégent,
Dragonne and
Elcano were a little further back. The allied flotilla opened fire on the Vietnamese forts and soon found the range. Marine infantry snipers, firing from the mastheads of the French and Spanish ships, picked off the Vietnamese gunners. The Vietnamese responded vigorously, but their aim was uncertain, and the French and Spaniards soon beat down their fire. The landing companies were sent ashore to assault the forts, and by 8 a.m. both forts were in Spanish hands. Later the same day
capitaine de frégate Bernard Jauréguiberry, the future French admiral and navy minister, scouted the
Citadel of Saigon aboard
Avalanche. On the morning of 17 February the French and Spanish went ashore and assaulted the citadel. Sergeant des Pallières of the marine infantry was the first to enter the citadel, and once the allies were inside the Vietnamese garrison retreated. A force of around 1,000 Vietnamese soldiers attempted to counterattack. Admiral Charner, who was personally directing the action, threw back their attack with Colonel Lanzarote's Filipino troops. At 10 a.m. the French and Spanish flags flew above the citadel. ==Allied occupation of Saigon, February 1859 – February 1860==