That is just theoretical stuff. Yes, theoretical there might be something like "treason" in some old law book .... But, I don't remember one "treason" prosecution in my life time in Germany, with exception maybe to the DDR-Spy with Willi Brand as chancellor ... wow is this long ago! Also, I think there should be filed charges against many people in Germanys current government because they don't stop the US to spy on German people and companies openly. But nothing happens.
Why, because in Germany there is no independent judiciary at all. There will be no prosecution without federal prosecutor, but all of them have to obey the government -- so no member of government or top politician will ever be prosecuted in Germany, whatever evil they do against the country or the people.
Germans should start understanding, that they don't live in freedom at all. It is just a mock-up.