New Year stationery from Hong Kong

During the last 2008 Autumn Stampshow in Paris, the new stamp sale company, Théodore Champion S.A., offered this to its clients:
a postal stationery of Hong Kong, transformed into a speciman. Red color, little format, I would say it is an envelope to send wishes, even gift in form of banknotes during the Chinese New Year festivities.

By the Hongkong Post website, three dollars frank a letter from 50 to 100 grams inside the region, under 50 grams to mainland China and Macau, under 20 grams to the furthest parts of the world. That would make many banknotes in the first two cases. But, as I can't find intels on registered mail...