What was the legal status of Berlin and the lost German eastern territorities between 1949 and 1990?

Question

West Berlin was not legally part of the Federal Republic of Germany (West Germany) and despite Communist claims, east Berlin was not legally part of the German Democratic Republic (East Germany). Territory to the east which fell within the 1937 frontiers of the German Reich but was not included within the borders of either post-war German state was technically under Polish and Soviet administration, but not officially annexed by those countries. And the last government of the Third Reich, headed by Grand Admiral Karl Doenitz, was not abolished, merely declared "incapable of acting" by the Allies.

Does this mean that, until the treaties permitting unification to come about in 1990, the German Reich technically continued to exist in Greater Berlin and the Laender of East Prussia, Upper Silesia, Lower Silesia, Pommerania and east Brandenburg?

What is the legal status of the territories east of the Oder-Neisse Line today? Have they been formally annexed by Poland and Russia?

Answer 1

Yes they are Russian States.

Answer 2

Between 1945 and 1990 there was no clear legal situation in Germany, because it took that long until a peace treaty was finally signed between Germany and the Allies to clarify the situation. Officially Germany wasn't a sovereign country till 1990 and there was only a truce in WW II, no peace.
The easternmost parts Silesia, Eastern Prussia, Pomerania and such were annexed by Poland and the Sovietunion. By their view they became part of these countries, official West-German view was that they were merely under their administration but still belonged to Germany. But already in the seventies in the Ostpolitik of Chancellor Brandt West-Germany declared that it would never use force to change these borders, which was a de-facto recognition of the Oder-Neiße line as the Eastern border of Germany.
The three western occupation zones formed the Federal Republic of Germany, which also included the western sectors of Berlin. Although because of the special status of Berlin, the city was in many regards not fully a part of the Federal Republic. The Berlin representatives had no voting rights in the German parliament, there was no draft, they had special Berlin-stamps for the post and so on. The Soviet point of view was that the western part of Berlin was a country on its own, they stressed that by writing it in one word Westberlin.
Officially East-Berlin should have had the same status but was incorporated into the German Democratic Republic which was founded from the Soviet occupation zone as an answer to the founding of the Federal Republic.
But the western allies still had several rights in East-Berlin. So they could come and go as they wanted and were not to be stopped by East-German border guards, which was an issue in the sixties.
The Federal Republic regarded itself always as the legal successor of the Third Reich, which meant for example that they didn't accept the East-German government as legal but it also involved that they took responsibility for paying compensation to Jewish people.
The East-German point of view was that they were a new country, had nothing to do with the Third Reich and had also nothing to do with West Germany. Whenver possible they used just the countries abbreviation DDR(GDR) and BRD(FRG) to avoid the common term Deutschland (Germany) in both names.
With the signing of the so called 2 plus 4 treaty (two Germanies and four allied powers) the unified Germany became sovereign, the allied occupation rights were abolished and Germany acknowledged it's eastern border to be the Oder-Neiße line and denounced any claims to Silesia and such.

Answer 3

Berlin was part of federal republic of germany.
technically all of it
however, it was divided in 4 zones (one for each allied country) , so de facto the 3 western sectors (US;UK and French) belonged to West-Germany and the soviet sector to east Berlin and GDR.

as far as i know after the reunification germany guaranteed the borders.
in some older german maps (from the fifties , 60s) u can see somtimes : german territories under polish / soviet administration .
There was no peace treaty so it was not clear if eastern parts of former (WW2) Germany would be given back or not.

in 1991 there was a treaty between poland and germany which made clear the parts of silesia ,,, etc east of the Neisse River belong to Poland.