Contrary to popular belief, the Gestapo was not the all-pervasive, omnipotent agency in German society. In Germany proper, many towns and cities had fewer than 50 official Gestapo personnel. For example, in 1939 Stettin and Frankfurt am Main only had a total of 41 Gestapo men combined. In Düsseldorf, the local Gestapo office of only 281 men were responsible for the entire Lower Rhine region, which comprised 4 million people.
"V-men", as undercover Gestapo agents were known, were used to infiltrate Social Democratic Party of Germany (SPD) and Communist opposition groups, but this was more the exception, not the rule. The Gestapo office in Saarbrücken had 50 full-term informers in 1939. The District Office in Nuremberg, which had the responsibility for all of northern Bavaria, employed a total of 80–100 full-term informers between 1943 and 1945.
The majority of Gestapo informers were not full-term informers working undercover, but were rather ordinary citizens who chose to denounce other people to the Gestapo.
According to Canadian historian Robert Gellately's analysis of the local offices established, the Gestapo was—for the most part—made up of bureaucrats and clerical workers who depended upon denunciations by citizens for their information. Gellately argued that it was because of the widespread willingness of Germans to inform on each other to the Gestapo that Germany between 1933 and 1945 was a prime example of panopticism.
The Gestapo—at times—was overwhelmed with denunciations and most of its time was spent sorting out the credible from the less credible denunciations. Many of the local offices were understaffed and overworked, struggling with the paper load caused by so many denunciations.
Gellately has also suggested that the Gestapo was "a reactive organisation" "... which was constructed within German society and whose functioning was structurally dependent on the continuing co-operation of German citizens".
https://en.wikipedia.org/wiki/Gestapo