His artistic approach centred on the female figure. He often depicted local factory workers and dancers in unforced poses. Rassenfosse preferred the subtle textures of soft-ground etching and lithography. In works like Staand fabrieksmeisje and Danseres, he used economy of line to suggest form. He avoided the heavy ornamentation of the period. His sketches of men and women are direct observations of Belgian life.

These prints appeal to modern buyers because of their minimalist aesthetic. The compositions are balanced and calm. His focus on the human silhouette provides a timeless quality. Collectors find that his work fits well in rooms with neutral colours. The sketches offer a sense of intimacy without being overly sentimental.