Recently, Germany’s FM Heiko Maas has said that HRM Thai King Maha Vajiralongkorn should not be conducting politics while staying in Germany:
"We have made it clear that politics concerning Thailand should not be conducted from German soil."
German MP Schmidt asked (highlight mine):
“Why does the German government tolerate this extremely unusual - and in my opinion illegal - behaviour of a foreign head of state conducting politics on German soil?”
Why could this be illegal at all, from Germany's view? If there any specific EU/German law preventing a foreign king to rule his country from German soil?
The Thai Constitution seems to have provisions allowing HRM exercise powers while being abroad. The absence of the King during the COVID epidemic has, indeed, triggered protests in Thailand calling to amend the Constitution, but (1) it is clearly in agreement with the Thai Constitution before any amendments have been ratified, and (2) it is about Thai Constitution, not the EU or German's.
Also, I'm aware that the EU and Thailand have tensions after the the 2014 military coup. But then again, it's not about members of a military junta (who can be accused of being undemocratic, for example), but about a ruling monarch of a recognized state.