I am living in Germany as aupair from nepal.

Ranjeena, it’s possible, but you need to apply for a visit entry permit if you go there for sightseeing purpose.
You should first prepare the following documents:
1. Copy of your passport
2. The filled-out application form attached with a recently-taken bareheaded color photo
3. Proof of your financial support
4. Transportation arrangement such as flight itinerary
5. Proof of your travel purpose to HK such as your travel itinerary
After, submit your application to the consulate general of PRC in Munich to apply for it. But if it’s the first time you apply for it, you should post your application to HK immigration department direct.