The current holders of a valuable violin are under growing pressure to pay compensation to the heirs of its Jewish former owner, whose family music shop was seized by the Nazis. The rare instrument, built in 1706 by the celebrated Italian luthier Giuseppe Guarneri, is worth approximately 150,000 euros, or around £133,200. But if it was repaired to its full glory, experts say it would be with at least $1 million. It came into Felix Hildesheimer’s possession in 1938. The music shop owner took over his father’s business in 1898 and bought the rare instrument from a Stuttgart-based music dealer...