The Tianjin Accord or Li–Fournier Convention, concluded on 11 May 1884, was intended to settle an undeclared war between France and China over the sovereignty of Tonkin (northern Vietnam).
The convention, negotiated by Li Hongzhang for China and capitaine de vaisseau François-Ernest Fournier for France, provided for a Chinese troop withdrawal from Tonkin in return for a comprehensive treaty that would settle details of trade and commerce between France and China and provide for the demarcation of its disputed border with Vietnam.
[1] Chinese opposition to French efforts to clamp a protectorate on Tonkin led to the outbreak of an undeclared war between France and China towards the end of 1883.
Chinese troops fought alongside Liu Yongfu's Black Flag Army during the Sơn Tây Campaign (December 1883).
Le Gouvernement français s'engage à n'employer aucune expression de nature à porter atteinte au prestige du Céleste Empire, dans la rédaction du traité définitif qu’il va contracter avec l’Annam et qui abrogera les traités antérieurs relatifs au Tonkin.
[5] Article I: France undertakes to respect and protect against aggression by any nation whatsoever, under any circumstances, the southern frontiers of China bordering on Tonkin.
Article II: The Celestial Empire, reassured by the formal guarantees of good-neighbourliness accorded to her by France as to the integrity and safety of the southern frontiers of China, undertakes: (1) to withdraw immediately to her borders the Chinese garrisons in Tonkin; and (2) to respect, now and in the future, the treaties directly concluded, or to be concluded, between France and the Court of Hue.
Article III: In recognition of the conciliatory attitude of the Government of the Celestial Empire, and as a tribute to the patriotic wisdom of His Excellency Li Hongzhang, the negotiator of this convention, France renounces her demand for an indemnity from China.
In fact, the Chinese stance was an ex post facto rationalisation, designed to justify their unwillingness or inability to put the terms of the accord into effect.
The war party called for Li Hongzhang's impeachment, and his political opponents intrigued to have orders sent to the Chinese troops in Tonkin to hold their positions.
China's refusal to pay an indemnity for the Bắc Lệ ambush led directly to the outbreak of the Sino-French War on 23 August 1884.