For salary, actually, maybe they won't propose you any increase but for sure living overseas will increase your living cost. It's the good time to negotiate with them. (And like all negotiation, you need to ask high increase (like 50%) if you want to have medium one (20-25%)
Yes moving allowance is important because it's cost between 2K and 4-5K EUR depending on how many items you have to ship (this is the industry I'm working in)
Last point for rental cost, I'm based in South China so I don't know the market in Shanghai but here, a nice 1-2bedroom flat is around 7K to 10K RMB (+ deposit + real estate agent commission). There are lots of furnished apartments in China, not like in France.
It's better for you to check this point on the famous French website " Bonjour Chine "