The expeditionary corps was established in June 1883 in the wake of Henri Rivière's defeat and death at the Battle of Paper Bridge, to entrench the French protectorate in Tonkin.

Bouët's first task was to secure the French posts in Hanoi, Nam Định and Haiphong against Black Flag and Vietnamese attacks.

Pressured by the civil commissioner-general Jules Harmand to attack the Black Flags as soon as possible in their positions on the Day River, he took the field in August 1883, despite the heat and humidity of the Tonkin summer.

Shortly before his resignation he recommended to the French government that the Tonkin Expeditionary Corps should be constituted as a regular two-brigade army division with the normal complement of artillery and ancillary support.

In the wake of Bouët's unexpected resignation, command of the expeditionary corps fell briefly to Lieutenant-Colonel Anicet-Edmond-Justin Bichot (1835–1908), the ranking marine infantry officer in Tonkin.

Among his many other talents, Courbet was a first-class administrator, and was deeply respected by the men of the expeditionary corps for the pains he took to ensure that military life ran as smoothly as possible for them.

Jules Ferry's cabinet approved this recommendation, and Courbet was replaced in command of the expeditionary corps on 16 December 1883 by General Charles-Théodore Millot—ironically, on the very day on which he captured Sơn Tây.

Having argued strenuously against sending a column to occupy Lạng Sơn in the heat of the Tonkin summer, he emerged unscathed from the official enquiry into the circumstances of the Bắc Lệ Ambush (June 1884).

In poor health, and dismayed at the way the French government used the Bắc Lệ ambush as a pretext for war with China, he submitted his resignation in September 1884.

In January 1885, on the eve of the Lạng Sơn Campaign, Colonel Ange-Laurent Giovanninelli (1839–1903) arrived in Tonkin and assumed command of the 1st Brigade.

Brière de l'Isle was a natural leader of men, and under his command the expeditionary corps achieved a high standard of professional excellence.

In October 1884, in the Kep Campaign, Brière de l'Isle defeated a major Chinese invasion of the Tonkin Delta, skilfully exploiting the mobility of the French gunboats to concentrate his forces successively against both wings of the Guangxi Army.

Although the French suffered heavy casualties in the Battle of Hòa Mộc (2 March 1885), they captured Liu Yongfu's blocking position and broke through to Tuyên Quang.

In May and June 1885 thousands of fresh French troops poured into Tonkin, swamping the veterans of the two brigades that had fought the Sino-French War, and the expeditionary corps was reorganised into two two-brigade divisions.

It was also memorable for a cholera epidemic which swept through the expeditionary corps in the summer and autumn of 1885, exacerbated by de Courcy's neglect of quarantine precautions, in which more French soldiers died than in the entire nine months of the Sino-French War.

Forbidden by the French government to launch a full-scale invasion of Annam, de Courcy landed troops along the vulnerable coastline of central Vietnam to seize a number of strategic points and to protect Vietnamese Catholic communities in the wake of massacres of Christians by the Annamese insurgents at Quảng Ngãi and Bình Định.

Key moments in de Courcy's intervention were the occupation of Vinh by Lieutenant-Colonel Chaumont in August, and the relief of Qui Nhơn and capture of Bình Định by General Prud'homme in September.

In November 1885 a so-called 'Annam column' under the command of Lieutenant-Colonel Mignot set off from Ninh Bình in southern Tonkin and marched down the narrow spine of Vietnam as far as Huế, scattering any insurgent bands that attempted to dispute its progress.

[6] In Tonkin, the expeditionary corps undertook a large-scale campaign in October 1885 to capture the Yunnan Army's old base at Thanh May on the Red River, occupied by Vietnamese insurgents under the command of Nguyễn Quang Bích since the end of the Sino-French War.

In March 1886 Lieutenant-Colonel de Maussion advanced up the Red River, meeting almost no resistance, and occupied the town of Lào Cai on the Chinese border.

[7] Although the Tonkin expeditionary corps eventually reached a strength of 35,000 men, it was never able to put more than a fraction of its troops into the field against the Chinese armies.

De Courcy, using a sledgehammer to crack a nut, concentrated 6,000 infantry, seven artillery batteries and three squadrons of cavalry for the October 1885 Thanh May campaign.

The battle of Palan (1 September 1883), a smaller affair, was fought by two marine infantry battalions (chefs de bataillon Berger and Roux), Roussel's battery and the Yellow Flags.

On 23 December the transports Vĩnh Long, Européen, Comorin and Cholon left Toulon to embark the Legion, Turco and Bat' d'Af' reinforcements at Mers-el-Kebir and Oran.

On 10 January the three line battalions, the artillery and specialist troops set sail from Toulon aboard the transports Saint-Germain, Poitou, Annamite and Mytho.

[11] In April 1885 the French government responded to the news of the Retreat from Lạng Sơn by arranging for reinforcements of just under 8,000 men to be dispatched to Tonkin.

Meanwhile, the armée d'Afrique was asked to furnish just under 4,000 men in fresh drafts from its zouave, Turco, Legion and African light infantry battalions.

It was also asked to send a third zouave battalion under the command of chef de bataillon Hubert Metzinger to Tonkin, and to provide a squadron of spahis and a half-squadron of chasseurs d'Afrique to swell the meagre cavalry contingent of the expeditionary corps.

Six companies of the 2nd Marine Infantry Regiment were detached from the Tonkin expeditionary corps in September 1884 to take part in the Keelung Campaign in northern Formosa.