Piece for Trombone and Piano by Joseph Guy Ropartz
Joseph Guy Marie Ropartz (1864--1955) was a French composer and conductor. His musical style was influenced by Claude Debussy and Cesar Franck. His "Piece in B-flat Minor" for trombone and piano shows the influence of both the romantic and impressionistic eras. Score for trombone and piano, and a separate score for the trombonist.
This performance of the piece will give you a taste of how it sounds, but your sheet music might differ from this artist's interpretation.