For this scenario, the answer unfortunately is "it depends." Although the National Socialist state and ideology made a big deal about creating a fundamentally new society, including legal codes, actually implementing such a thorough restructuring was much more difficult to achieve in reality. Although the Third Reich instituted various laws and discriminatory decrees restricting racial and political enemies as well as greatly expanding the arbitrariness of criminal law, civil law procedures remained largely untouched (with the notable exception of marriage which became racialized), at least for those deemed Aryan. Many Germans continued to operate under the impression during the Third Reich that it was a Rechtsstaat (a society of laws) and still enjoyed access to the courts for private legal matters. The Justice Ministry toyed with replacing the existing civil law, many of whose statutes dated back to the nineteenth century, with a National Socialist Volksgesetzbuch (people's law) during the war, but this was never really accomplished. The genesis of the Volksgesetzbuch was rooted in the idea that existing civil law was too liberal and not concerned about protecting the racial community.

So two Aryan business partners suing each other in 1942 would in theory have a fair trial. However, some important caveats are in order. For one thing, while the Third Reich did not destroy the existing civil statutes, it was fairly successful in Nazifying the German legal profession and the state's jurists. Through both pressure on legal schools as well as self-coordination of an already fairly conservative profession, most of the Third Reich's jurists held views that were largely in line with the ideals of the state. Thus if a case had an ideological gloss or aspect to it, the court could tilt one way. Additionally, the war encouraged a much more arbitrary use of justice in defense of the Volksgemeinshaft (racial community). Harsher penalties and greater leeway for judges' intervention in cases became very typical for German criminal cases, and this sort of prerogative could apply in civil cases as well. Finally, legal cases did not take place in a vacuum and a plaintiff or defendant's personal connections to the NSDAP was also something that could matter. Personal intervention by Party members could negate settlements or impose them, and this was a tendency that increased as the war became more desperate.

Interestingly enough, a good many Germans living within the Third Reich did believe they were living in a Rechtsstaat. Civil courts remained open to the privileged majority and even the existing criminal codes still applied some degree of legal protections for Aryans. One of the turns in German popular opinion against the regime was when the regime started to circumvent these German civil liberties. One of the more curious incidents during the war was when Hans Frank, the brutal and venal head of the General Government in Poland, went on a German lecture tour in 1943 1942 warning that SS-led encroachments on civil liberties was so dire that Germany was in danger of becoming a police state. Frank himself only lost his titles and some of his perks for this tour, but it demonstrates the wider belief that this dictatorship was somehow benefiting the majority of Germans without violating the law. For most Germans, it mattered relatively little that starting in the 1930s their legal system developed a twin-track of a privileged majority and an undesirable minority, nor that the legal profession mirrored the state's ideology. It was only after the Third Reich began to turn on them that opinions began to change.

Sources

Steinweis, Alan E., and Robert D. Rachlin. The Law in Nazi Germany: Ideology, Opportunism, and the Perversion of Justice. New York: Berghahn Books, 2013.

Wachsmann, Nikolaus. Hitler's Prisons: Legal Terror in Nazi Germany. New Haven: Yale University Press, 2004.