8th January 1889
|Sc1 SG2||Sc2 SG1||Sc2a SG1b||xxx|
|Surcharges on stamps of French Colonies, general issues|
|5 centimes on 35c deep violet, orange||Black||1||2|
|5c on 35c deep violet, orange||Red||2||1|
|5c on 35c deep violet, orange ‡||Red||2a||1b||Date smaller font|
† Scott  lists the black surcharge first and dates in as 8th January, then the black surcharges and dates them 10th January.
Gibbons reverses this: red first on 8th, black on 10th.
‡ Three stamps on the sheet of 25 with the red surcharge had the date of 1889 in a smaller font. Pairs of the two types do exist and an image is being sought.
To summarise Mackay , the French conquered the area in late C19th and gave it the name Indochina from 1888 onwards, covering the colonies and protectorates of Cochin-China, Annam and Tongking (Vietnam) and Cambodia. Later additions were Laos (1893), and Kouang-Tcheou (1900).
Mackay notes that with "an area greater than France itself, inhabited by people of diverse races … it is not surprising that colonial rule was resisted to a greater or lesser degree". The resistance was greatest in Vietnam, eventually leading to the Vietnam War.