The French CAC-40 index is a French stock price index, which consists of 40 French stocks. Prepared by PSE Stock Exchange according to the share prices of its top 40 listed companies, with a base period of 1987. The index was released on June 5th 1988, which reflected the price fluctuation of the French stock market. China investors' attention to the securities market mainly depends on this index. It is not clear how many listed companies have issued securities, but at least CAC40 can better reflect the situation of the French securities market.