IIRC, they don't fully occupy it à la Germany post-WW2, but are heavily present for humanitarian aid and cultural exchange. The 2nd "The Fall" book describes the situation with strong analogies to occupied Iraq, as far as I can see.
To my knowledge, there was no resistance in West-Germany. Perhaps because the denazification was soon stopped after the high ranking Nazis had been tried, and the many middle and low rank Nazis were integrated into the new system:
The 50s and 60s in West-Germany were a time many people even considered a kind of "Nazi restauration", as many leading positions were occupied by former Nazis and society, outside of academia at least, featured a kind of "let's not mention the past!" atmosphere. German crimes were hardly ever mentioned, and when the war was a topic, it was mostly to mourn the German victims -- poor Germans expelled from the eastern regions, poor Germans bombed by the Allies. (Until 1961, there even was a party representing the interests of the expelled Germans in the parliament. Their main demand was gaining back the lost territories.)
Among the most prominent examples of lesser Nazi ranks were first Chancellor Adenauer's (CDU) chief of staff, Hans Globke, who had been co-author and chief commentator of the racist 1935 "Nuremberg Race Laws", or the 3rd Chancellor Kiesinger (CDU) from 1966-69, who had been Nazi Party member as a student. It would happen that Chancellor Adenauer (CDU) referred to the "superior influence of international Jewdom" in his speeches to justify his pro-Western stance -- "better don't mess with the Jews, they're too powerful". Until the 70s, even newly printed maps would show Germany in the borders of 1937, while the eastern territories were only marked as "currently occupied by Poland/USSR", because the government did not officially accept the division of Germany.
The very conservative governments (dominated by the then very conservative CDU) between 1949-69 more or less continued the Nazi propaganda -- down to some of the same slogans and narratives -- against the Soviets. Many former Nazi propaganda experts were employed by the Western Allies and the West-German government. Only difference being the Americans were now painted as "big brother" helpers and friends against the Bolshevist threat, the last best hope for saving Western civilization from the eastern hoardes. Especially the Berlin Airlift 1948/49 and America's support during the Berlin Crisis 1958, then Kennedy's Berlin visit, were very crucial for changing the West-Germans' view of the Americans.
So most former Nazi sympathizers were won over for the new system, while the few remaining hardcore Nazis, who had founded the largely unsuccessful "German Reich Party", were ostracized. Their party was banned in 1953, IIRC.
It's a great achievement of the conservative CDU/CSU to integrate former Nazis, the German right in general, into a democratic system. It was the first time in German history that the right actually embraced liberal republicanism, at least most of the right. The CDU/CSU governments also sealed tying West-Germany into the Western political order, and ending the view of France as "arch-enemy" (that view dated back to the Napoleonic Wars and had been central in nationalistic propaganda on both sides) by establishing a very tight cooperation.
All this changed with a new generation coming of age. A radical leftist student movement, sourrounded by a less political hippie-influenced generation, waged a couple of protests and uprisings around the universities in 1968. Albeit inspired by the civil rights movement, anti-Vietnam war protests and other such movements in America and elsewhere in the West, the German variant of this movement had a decidedly more political, radical leftist flavor.
The hard core of these "68ers", as they were called, radically denounced the new system as "post-fascist" and the difference between actual Nazi rule and the new reality in the republican system was blurred in their eyes, instead they favored communist alternatives; some even joined pro-Mao or pro-Vietcong political groups (so called "K-groups"). They often didn't see fundamental differences between the Nazis' imperialism and the alleged imperialism of the USA in Vietnam; as America apparently supported their former Nazi Allies in the West-German government, they can't be fundamentally different. On top of that, it was a massive generational conflict, of course, when the children of former Nazis started asking their parents uncomfortable questions, and radically rejected their claim of authority, as their parent generation had forfeit all authority whatsoever in their eyes, due to their Nazi guilt.
The less extreme "68ers" soon became more moderate as they grew older, and eventually embraced the free system. They found a focal point in the first (moderate) left-wing West-German post-war government: In 1969, the moderately left-wing SPD won the election for the first time, Willy Brandt became Chancellor, and made German guilt a topic (perhaps you remember him falling on his knees at the Warsaw Ghetto memorial). The new SPD/libertarian FDP government (1969-82) thoroughly reformed the conservative post-war society, sought to integrate the new young generation, and democratized society further. A common dictum back then was "now finally, Hitler has really lost the war" (after Brandt had become Chancellor).
A hard extremist core of the "68ers" formed a terrorist group, called Red Army Faction (RAF) and committed many bloody terrorist attacks, kidnappings and even an airplane hijacking throughout the 70s; the moderate left government took many efforts to prosecute them. This situation reached its peak in the "German Autumn" in 1977, when Chancellor Schmidt (SPD) was ready to resign, if an anti-terrorist action had been unsuccessful (but it succeeded).
I guess by the mid 80s, the change of society had reached a saturation point: Most real old Nazis had retired or died by then, and even a right-wing President (Richard von Weizsäcker, CDU) called May 8th 1945 "a day of liberation" even for the German people -- it caused moderate uproar among very conservative people, but the vast majority accepted this statement.
And the new CDU/CSU government by Chancellor Kohl didn't attempt to set back the clock either, after regaining power in 1982, but more or less accepted most reforms their left-wing predecessors had enacted. There had been two successful, democratic changes of power via elections, and political scientists called this a proof for the maturity of the new republican system.