Annam (Indochina)

The Empire of Annam was under French protection since 1886. I've seen an old state flag, that was yellow with two "eastern" (Chinese or Annamite) written-characters in black. After 1886 the yellow flag included the French tricolor in the canton. The national flag was three horizontal strips yellow, red, and yellow.
Jaume Ollé - 23 September 1997

A triangular flamuled pennant with the lower edge ortogonal to the hoist, yellow with red orle (inner bordure) with the dragon emblem covering the triangular field. Above the pennant is a yellow and red bicolour long pennant.
Željko Heimer, 27 November 2004

A rectangular standard higher then long - an orange field bordered green and red (red outside) and with blue falmmuly border on three outer edges, In the orange fields there is the dragon. Above the flag is an orange long pennant with green and red ornaments.
Željko Heimer, 27 November 2004

A yellow flag with the French tricolour in the canton. as with some other French colonial flags of the period, the tricolour height is equal to 1/3 of the hoist.

The 1926 Flaggenbuch [rwm26] shows the same flag captioned National Flag. Jaume gives this flag in square format with square Tricolur 1/2 the hoist high, which might have been a variant.
Željko Heimer, 27 November 2004