However, as the political climate in Berlin changed, most notably for Jews, and became more threatening, he decided to move first of all to Brussels from 1934–1937, and later to Paris from 1937 to 1939, and then on to the south of France.
During the early years of his career, Hermann used to visit London for recitals and concerts and then would stay at the de Graaff-Bachiene family residence, owned by patrons of the arts.
Hermann and his friend Zoltán Székely had entertained a large company of people in the De Graaff household in London in 1928, at the peak of their musical partnership, with a house recital.
Later that evening, Hermann had been the centre of attention during the after-concert soirée that followed and had jokingly started to dance with his own cello in his arms.
To bring the evening to a happy ending was their host Jaap de Graaff, patron and protector of the arts, who decided to buy a Gagliano cello for Hermann, and a Stradivarius violin for Székely.
No recordings of Hermann as an artist are known to survive, although he often performed recitals, or as a chamber musician with the Hungarian Quartet, with violinist Zoltán Székely and others.