I do not have more information about the date in question, but I have run across the following in Malama Melseisa's book "The Making of Modern Samoa: Traditional Authority and Colonial Administration in the Modern History of Western Samoa." (1987) Institute of Pacific Studies of the University of the South Pacific.

"Tamasese had visited Germany in 1910, where it had been intended to display him with party of Samoans among specimens of natives from German colonies behind bars in municipal zoos. Tamasese was accompanied by his wife, his son and two daughters, his tulafale 'Ai'ono, two taupou, eight young girls and some children "who presented dances, boxing contests, games and preparation of Kava" (Riedel 1938:218). Otto Riedel, who had been manager of DHPG in Samoa observed:

"Tamasese had quite a different idea about his visit from that of his manager. He regarded it as a kind of visit with new friends. He did not like the idea that he was to be shown in zoos, especially as he was not worthily accommodated. Marquardt [the manager] apparently did not want to let him see me. But Tamasese had simply climbed into a car with his wife and said to the Hamburg chauffeur "Otto Riedel!" He could not imagine that there was anyone in Hamburg who did not know me. The chauffeur to whom Tamasese, of course, could only make himself understood through gestures, behaved very sensibly. He looked up the telephone book, found my address there and brought his exotic guests exactly where they wanted to go (Riedel 1938:218)."

Reference cited:

Riedel, O., 1938. Der Kampf um Deutch -- Samoa, Erinnerungen eines Hamburger Kaufmanns. Berlin.

Oh, on a related matter. Samoans were also in a way "on display" around the same time period (1893) in the United States as well. Except, rather than in Zoos, it was at least at one World's Fair, the Columbian Exposition in Chicago. The Samoans along with other culture groups such as the Javanese and Laplanders had small "village" set ups at the "Midway Plaisance" at the fair. In one book, entitled "Grand Illusions:Chicago's World's Fair of 1893" by Neil Harris, Wim de Wit, James Gilbert, and Robert W. Rydell. (1993) Chicago Historical Society, there is a photograph of some of the Samoans there.

CAPTION: This ususual candid shot captures a visitor's shocked reaction as the half-naked Samoan Villagers parade by --not the ordinary, stolid and posed shot of the 'Midway types.'"

Detail showing where the "Samoa Islanders" were in the midway (the detail was taken from a book entitled, The Chicago World's Fair of 1893: A photographic Record: Stanley Appelbaum.) If you look at the Midway Detail map they are to the right under the N of the word PLAISANCE.