score:5
Here's a community wiki to add to if there are more than these two:
Embassy in Hanoi, as expected:
Consulate in Ho Chi Minh, as expected:
These first two answers are from Wikivoyage. I went through each page for each city in Vietnam and did not find any others. But you never know ...
The Wikipedia page on Chinese embassies and consulates around the world agrees that these are the only two.
The "Embassies > Asia" and "Consulates General > Asia" pages on the Chinese Ministry of Foreign website also agrees these are the only two.
Upvote:2
Searching in French fortunately yields fewer spam results and many forum/blog posts. There is definitely an embassy/consulate in Hanoi were foreigners can get a visa (here is a very detailed description by someone who did get a visa there a little over a year ago).
Wikipedia also says something about a consulate-general in Ho Chi Minh City but no details on whether you can get a visa there. The website of the French consulate-general in Ho Chi Minh City also mentions it, with contact details.