I had never thought of what happened to Germany's embassies and ambassadors at the end of the war up until now. For the countries that still held diplomatic relations with Germany by the war's end, did the German ambassadors remain there, or were they recalled to Germany? Since Germany was under occupation I'd assume they would've had to return to Germany? I assume the same would hold true for Japan. I would assume Italy would've just had new ambassadors assigned once Mussolini was deposed and the new Allied-friendly government was established. Would anyone have better info on this or even perhaps a book that sheds more light on it?

Italy declared war on Germany after Mussolini was removed so I doubt they had embassies.

I read about this decades ago, so I don't have exact country by country information. However, it has been a tradition throughout History that when war occurs, ambassadors have been granted "safe passage' out of the hostile country.

In WWII as in World War I before and because of the number of belligerents involved, there were 3 categories of actions took by differing countries from what I can remember.

• Host Country granted safe passage out by a time specified
• Host Country effectively put Embassy and personnel under "house arrest;" if they had to leave the Embassy compound, they went under guard and were returned under guard.
  
• Host Country interned all Foreign personnel in a prison camp.

These modern times, post WWII, with the rise of International Revolutionaries, all those old archaic bourgeoisie laws, treaties, customs are gone.  

By law, which still stands, they are allowed to leave or are detained and exchanged.