Insider trading is it course not legal for politicians in Germany, as you could have found out without being a lawyer.
That being said, transparency/reporting duties for members of parliament/ministers can and should definitely be improved.
Which I may add: you could've easily found out yourself too if you looked up what I wrote.
Are you sure about that? European legal theory for insider trading implicitly covers more cases than the US without needing to explicitly enumerate them as far as I understand (in a nutshell, trading on insider information is illegal regardless of the source or whether any fiduciary duty was breached), and I'd be surprised if this case were not covered.
The issue in America is the president has more power to act unilaterally (maybe to address his/her own interests, maybe not) than any European politician.