Meinhard Matern, deputy mayor of the alliance's newest member Bad Homburg, said seeing the positive experiences of other cities made joining the alliance an exciting prospect.

"We have already had tourist relations with China as we see many Chinese visiting our city, but we want to strengthen also our economic relations between Chinese and German companies in Bad Homburg," he said.

The city of Dortmund has also been given observing member status after expressing its interest.

Pascal Leiden, vice-director of Dortmund's Economic Development Agency, said: "With this alliance, our companies will find it easier to access the support, the contact as well as the network once they go out to China to look for opportunities."