“Belleville needs high engineering – visually and physically the chair follows a strictly defined purpose and precise design“, explain Ronan and Erwan Bouroullec. The Belleville Chair is a technically sophisticated hybrid chair of two components – a structural frame in polyamide and a seat shell available in different materials. A slender black frame traces the calligraphic lines of the legs and back of the chair. The contour of the back of the Belleville side chair follows a continuous rounded trajectory. The curve of the Belleville armchair, which has forward slanting armrests, changes directions twice and then resumes its momentum. In both versions of the chair, the slender black frame supports an extremely thin shell that tapers from the wide seat surface into a narrow backrest.