The Nguyễn dynasty Vietnamese defenders suffered heavy losses including, at his own hand, Governor Hoàng Diệu, following the dispatch of a final message to the Emperor Tự Đức in Huế.

[1]: 345–347 [9] On the first day of Henri Riève's arrival in Hà Nội, Hoàng Diệu authorized mandarins Tuần vũ and Án sát [vi] to welcome him.

Seeing the French army coming in large numbers and intending to station in the citadel, Hoàng Diệu urged the defense and ordered to bring back more troops from surrounding provinces.

The commander of the French army asked the Đại Nam side to withdraw their troops and cancel all defense work, of course Hoàng Diệu did not accept.

[1]: 349 On 25 April 1882, Captain Rivière sent Governor Hoàng an ultimatum at 5 A.M, declared that until 8 A.M, without a troop withdrawal, and the Vietnamese military officers do not come to surrender at Đồn Thủy, the French will attack the citadel and will rearrange everything so that there is no harm to them.