China's leaders may be touting efforts to offer foreign investors a level playing field, but on the ground, protectionism appears to be growing, Germany's ambassador to China told CNBC.

"It doesn't matter which trading partner you talk to – be it the Japanese or the U.S. or neighboring countries or European countries. They all feel the same, that there's a growing protectionism here," Michael Clauss, the German ambassador to China, told CNBC's "Squawk Box" on Monday.

He noted that the protectionist concerns related to German investments within China.

"The service sector is basically off limits. Many companies that would like to produce here in China and build a factory and start producing are forced into going in a joint venture," he noted. "It's also frequently they're asked to transfer technology, which is against the rules of the WTO. And the tendency seems to be growing. That's the complaint we get from German businesspeople."

But Clauss pointed to signs that Chinese rhetoric on trade and investment has been changing.