Why do ADRs exist? These certificates are used to make foreign companies easily tradable on a US stock exchange. As a shareholder from Germany, we would not be allowed to buy Chinese shares at all.
@TimLie China has banned foreigners from acquiring shares in certain sectors. You can then only participate in the share price performance viaADRs. I can't tell you whether Xiaomi falls into one of these sectors or whether you had an ADR.