Unless you speak French, otherwise it is not possible to stay in France. Besides, HEC is mostly famous within french company circle. If you go back to China, means no much.
With Ox, maybe you can stay in UK for a while. Their alumini work is very powerful and the name have more value if you return to China for a job.
no one will regret studying in Oxford. It is more a life experience than simply education. Imagine wearing the sub-fusc, attending all-latin degree ceremony, the unique exam school...etc