Mary Roberts Rinehart 
The Street of Seven Stars [PDF ebook] 

It is a story of growing love between a poor music student Harmony and doctor Peter Byrne. Since her friends have left Vienna to return to America, Scatch to marry her sweathart, and the big soprano because she isn’t good enough, Harmony has a home problem. She has to leave their apartment and search for a cheap room. Finally she finds an affordable room in pension Schwarz, where she meets Peter and dr Anna Gates.
Together they decide to take an apartment and all is well to the moment Anna has to go back to America.
Anyway, this is one of her non-mysteries, here in pre-World War I Vienna. The main plot/romance between a budding violinist and a student doctor is OK, at best, but there are all sorts of supporting characters that make this worth reading – a dying boy, a guard, a student’s mistress, a Bulgarian spy, a female doctor beginning her spinsterhood…