This 1856 treaty formalized French extraterritorial and commercial privileges in Siam, shaping Franco-Siamese relations through Western imperial expansion for nearly seven decades.
Key Facts
- Date signed
- 15 August 1856
- Number of articles
- 24
- Import duty rate
- 3 percent (fixed)
- Duration in effect
- 68 years (until 1925 treaty)
- French negotiator
- Charles de Montigny
- Siamese king
- King Mongkut (Rama IV)
By the Numbers
Location
Cause → Event → Consequence
French imperial expansion into the Far East under Napoleon III created competition with Britain. Siam sought to balance British influence by cultivating ties with France. Building on the Anglo-Siamese Bowring Treaty of April 1855 and the Sino-French Whampoa Treaty of 1844, Napoleon III dispatched Charles de Montigny to Bangkok to negotiate a formal diplomatic and commercial agreement.
Montigny arrived in Bangkok in July 1856 and negotiated with five Siamese plenipotentiaries appointed by King Mongkut. The resulting treaty, signed on 15 August 1856, established French consular authority, extraterritorial jurisdiction, a fixed 3% import duty, freedom for Christian missionary activity, and rights of residence and land ownership for French subjects near Bangkok.
The treaty remained in force for 68 years and gave France leverage to employ gunboat diplomacy against Siam in 1865 and 1893. French extraterritorial jurisdiction was partially curtailed by the 1907 treaty, which required Siam to cede northwestern Cambodian territories. The 1925 Franco-Siamese treaty, negotiated by Francis Bowes Sayre, finally abolished most terms of the 1856 agreement.
Political Outcome
Siam granted France extraterritorial jurisdiction, a fixed 3% import duty, freedom of Christian proselytization, and rights of residence near Bangkok; France gained significant commercial and diplomatic privileges in Siam.
Siam had no formal Franco-Siamese diplomatic treaty since the late 17th century under King Narai and Louis XIV.
France secured extraterritorial rights and commercial concessions in Siam, establishing a formal imperial presence alongside Britain.