A growing economy needs investments. One way for companies to receive money is to sell stocks to investors by dint of the stock exchange. So investors can diversify in countries which former were inaccessable markets.
The restrictions to become a fully fledged member on a stock exchange like the New York Stock Exchange are very strict. Only a few foreign companies, all of them with high market value, are listed on the Nyse. But there are also ways to have a listing as an American Depositary Receipt (ADR). In this manner you can buy also many Chinese stocks.
Such stocks may be of high volatility since the interest of investors are pretty various. But it is a good opportunity to participate in the growth of the Chinese markets. Some of these stocks also pay dividends, so you get a continuous return on investment.
In Germany there are very few listings in comparison with New York Stock Exchange.