BRUSSELS — As Prime Minister Wen Jiabao of China tours Europe this week, it is no accident that Germany occupies a special place on his itinerary.

After all, Germany is the one European Union country that has a trade surplus with China. And it has also been a focus of Chinese investment in Europe — so much so that analysts say some Germans are growing wary as Chinese businesses have been snapping up German engineering companies.

Mr. Wen, making his sixth visit in eight years, and the German chancellor, Angela Merkel, on Sunday opened the annual trade fair in Hanover, billed as the world’s leading showcase for industrial technology.

They plan to witness the signing of an economic agreement at the Volkswagen headquarters, in Wolfsburg, on Monday. According to German media reports, the deal will include the opening of a new car plant in the far western Chinese region of Xinjiang.