Just like many westerners, it took me some time to understand how the first/last name etiquette works in China. Thankfully, thanks to Wu Chenli, one of my former students, I finally got it or, at least, I got it less wrong in the context of a professor/student relationship.
Just to make it clear for all westerners, in China the last name (usually monosyllabic) comes first and the first name comes afterward. For instance, when referring to the president of the PRoC, you should say Xi Jinping (last/first name; like “Smith John”) or, to mark respect, use a combination of title plus last name — Mr. Xi or President Xi.
Just like in most western cultures, using just Jinping (e.g. “John”) is colloquial and friendly. This is the way you would talk to a friend or a member of your family. Yet, there is an exception: when talking to a friend whose first name also is monosyllabic (e.g. “Liu Han”), you should use his full last/first name as calling someone with just one syllable (“Han”) sounds weird to most Chinese people (not rude, just weird).
To sum it up, as a teacher talking to one of my students, I should use the “Wu Chenli” form unless I want to reduce distance between us in which case I may use “Chenli”. The other way around, my students would call me “Mr. Nicoulaud” or “Professor” (which is much less formal that we think) and may, in a more friendly relationship, use my first name.
To be clear: I’m pretty sure that my depiction of the Chinese system is simplistic and that there are myriads of nuances and social conventions I’m not aware of. But if you think about it, most of the difference between the French system and a Chinese system may be safely summarized has: “just reverse the last/first name order” — full stop.
(If you are Chinese, either by nationality or culturally, your comments and objections are highly appreciated.)