The German state should “in very important cases” block foreign firms from buying up companies working on key technologies by itself stepping in as an investor, Economy Minister Peter Altmaier said yesterday.

“The state should only be able to buy shares in a company in very important cases and for a limited time,” Altmaier said at a Berlin press conference outlining a “national industrial strategy 2030”.

“We plan to create a national investment mechanism” to implement the scheme, he added, promising clear rules rather than “capricious” decisions on when to intervene.

Altmaier’s project is a marked break with conventional German economic thinking, which prescribes minimal state involvement in markets.

But since 2016, when China’s Midea took over Bavarian industrial robot maker Kuka, politicians have been sounding the alarm about vital building blocks of German prosperity being sold off—especially when Beijing is in the background.