Through written and pictorial materials, especially French documentation, the article offers a variety of lively information to help the reader imagine a development stage of "hat boi" (Vietnamese opera), "nhac tai tu" (music of amateurs) and "cai Iuong" (reformed theatre) in southern Vietnam in the late 19th century and early 20th century. Accordingly, at that time, "hat boi" and "nhac tai tu" were performed several times in France through international fairs, and the earliest fair was held in Paris in 1889. "Hat boi" had held a fascination for the French audience, even affected some of Debussy's compositions. Those performances helped the artists more confident, and after returning home, they fearlessly performed in public. It was then that the performances on stage of "nhac tai tu" and "ca ra bo" were common, leading to the birth of "cai Iuong", a new genre of the theatre.