Hitler's seizure of power, early in 1933, brought Gál's career in Germany to an abrupt end, on account of his Jewish origins. The National Socialists occupied Mainz in March 1933 - the city was in no way a Nazi hotbed, and in fact a detachment had to be sent from Worms to achieve this - , hoisting the swastika on public buildings, including the Conservatory, and articles soon appeared in the local press denouncing 'the Jewish control' of the conservatory - one concluded with the words 'Away with the Jew Gal. Mainz Conservatory for German Art!'. On 29th March he received a letter from the authorities with the brief communication: 'I hereby suspend you with immediate effect.' His secretary recalled that 'Director Gál just picked up his hat and went'. But it was not only his employment that was lost; all performances and publication of his works were henceforth forbidden in Germany, depriving him at a stroke of his livelihood. The violin concerto had had its first performance one month earlier, but the opera Die Beiden Klaas, which was being prepared for performance by Fritz Busch in Dresden, could, as a result of the events in Germany, no longer be staged (more).

At first Gál protested vehemently against his dismissal, invoking - in vain - a clause in the law which exempted from dismissal those 'non-Arians' "who had fought at the front for the German Reich or for its allies in the World War". He was reluctant to believe that this situation could last. Shortly after Hitler had become Chancellor, Gál had attended a concert on the occasion of the 50th anniversary of Wagner's death at which Hitler was also present, sitting near him. Gál had looked carefully at Hitler's face and concluded that no-one could possibly take him seriously. Events proved him tragically wrong.

The family remained in Mainz, but it soon became clear that they could not stay there, if only because they endangered their many friends, whose visits to the house to express sympathy and support were carefully monitored by Nazi sentries at the door, and their children were also being subjected to abuse at school. They therefore left to stay with acquaintances in the Black Forest (in the children's home where they had already gone for short holidays), from where Gál continued to pursue his legal claims, which, incidentally, dragged on for a year. He also managed - characteristically - to continue composing even under these desperate circumstances, the result being his Nachtmusik (op. 44), for soprano, male-voice choir, flute, cello and piano, to a poem by Grimmelshausen, the text of which runs, significantly, 'Come, O nightingale, consolation of the night'. Later that year, unwilling to cut his ties with his cultural roots by emigrating, Gál and his family returned to Vienna.

One final note: the Gáls' landlord in Mainz refused to accept any rent for the period between April and August 1933 - his own personal protest against the Nazi regime.