Hehe, there are quite a few French people in China, as long as some Chinese students learning French...
But of course, English is more common over here :)

1) For the textbooks, there is a much larger choice than in France, and you can even find some material in French.
I know a big library in Shanghai providing this, I'm sure that's also the case in Beijing.

I cannot recommend a book in particular, but you can try several of them for the prices are generally much lower than in Europe... And of course you can spend some time in the store to look inside the books ^^ I'm sure you will find something that suits you.

2) For the cultural part, I would say, maybe the mentality of Chinese people. They are not the same as we generally depict them in Europe... But this is not "shocking" at all, it's rather a surprise.

Have a good time in China!

Ah, the french. When will you stop demanding that tout le mond speak your language?

I hope you had a nice chat with the flight attendants of that airfrance flight, because those are probably the last french speaking chiense you'll ever find.