To work in certain medical professions in Germany, you may need to seek recognition of your qualification first, if it was obtained outside the EU. You can find more on whether you need an official recognition and where to obtain it here:
www.anerkennung-in-deutschland.de/de/interest/finder/profession.
For additional, detailed information on the procedure for recognition of professional qualifications, please refer to the website "Make it in Germany”:
www.make-it-in-germany.com
In principle, medical professionals from Hong Kong can also apply for recognition of their titles in Germany.