For a German on a trip to Shanghai, are there some surprising business rules which could lead to some kind of embarrassing situation? Is there something which would be considered especially rude by a Chinese engineer, if his German co-worker does it?
Wikitravel has an (understandably) massive article on China.
However the two sections that may interest you are:
Understand - People and Habits - why people do or don't do certain things in China
Respect - how to avoid faux pas in China
When in doubt, be conservative, polite, and follow the lead of your hosts.