The Rhapsody for clarinet and piano, (or orchestra) by Claude Debussy is one of the most characteristic of the French repertoire written for the clarinet during the last century and it remains of of the more difficult to execute in the proper style, really what one can call the "French" style. It is simply the best work in this style ever conceived for the clarinet. And, the execution of this work is full of misconceptions which can turn the work into one of great sterility and complete absence of its diaphanous quality.
Like the great Impressionist painters of several decades prior to its conception, it creates a kind of living snapshot of this beautiful ambience made up of whispering legato phrases, in a most syncopated manner, yet never sounding anyting but really buttery layers of sound by both clarinetist and pianist, regardless of the rhythmic mechanics written down.
As clarinetist, you must first choose a pianist who has played Debussy, the Preludes perhaps, and who understand real pianissimi in the context of accompaniment.
For you, as clarinetist, this work requires your most flexible reed and truest intonation able to both whisper and to to articulate forcefully when necessary.