I am studying in china but wants to go paris as a tourist but I belong to another country

You should first provide the required documents including 2 recent and identical identity photos, the completed application form, Chinese residence permit, round-trip flight tickets booking, studies certificate or diploma, student card, bank statement covering the last 3 months, travel itinerary, hotel booking, travel insurance, and your passport and copy of its data page as well as other documents the consular officers consider necessary.
Next, submit your application to TLScontact center in Beijing to apply for French tourist visa. It may cost RMB432. Just for a reference. The final payment is subject to the actual payment given by the consular officers.

if I book my round trip flight ticket and hotel booking but the embassy rejected my application then what will I do about it?

do you know how much will the expense of visa? total expenses

Generally speaking, you won't be rejected by the embassy as long as you meet all requirements. It may cost you RMB432 in total. Just for a reference.