It depends on the instrument and tuning system. In 12-tone equal temperament they are the same. Some tuning systems treat them differently though, in fact some

It depends on the instrument and tuning system. In 12-tone equal temperament they are the same. Some tuning systems treat them differently though, in fact some early keyboards had separate keys, the black keys were split in two so D# was a different key to Eb. Called "split sharps". https://en.m.wikipedia.org/wiki/Split_sharp https://en.m.wikipedia.org/wiki/Split_sharp