Fersen is an accomplished poet who regularly plays with language, using puns, rich rhymes, symbols and images taken from the realms of plants (vegetables and fruits) and animals (birds and various beasts) to tell stories or original fables, to recreate moments from daily life, impressions and sentiments, and also the dreams of ordinary people and their failings and faults.
His deep and gravelly smoker's voice gives a particular tone to his songs, which belong to different musical styles depending on the album (rock, folk-rock or jazz and blues).