https://www.focus.de/politik/ausland...195396848.html
Article about Bundeswehr pilots training the Chinese on
Qiqihar airbase in Heilongjiang province. This supposedly started in 2013 when a certain Alexander H. ( normal German practice just to give initial only ) retired at the age of 41 moved to China. He is working with Lode-Tech, a company owned by Su Bin, who had previously run an aerospace company in Canada. He was arrested in 2014 and confessed that he had been spying for China for six years, collecting aerospace information ( strangely there is no report of any punishment )
There is no German law preventing this, but a parliamentary sub-committee is now reviewing the situation.