In his Arc-en-ciel no. 5 (Rainbow no. 5), the painter Delaunay imagined a rainbow—opaque bands of violet, indigo, green, yellow, and bright red—spanning a dense forest with a blue mountain in the distance. This richly pigmented landscape at first appears to be a generic one; yet the Eiffel Tower, just behind the rainbow, enables us to identify the scene as an idealised version of Paris. The steel towel, here, rendered with a few gestural strokes of lilac paint, was an instantly recognisable icon of Delaunay's native city. At the time that Delaunay painted Arc-en-ciel no. 5 (Rainbow no. 5), the Eiffel Tower was also the tallest manmade structure in the world, and thus a powerful symbol of modern human ambitions and achievements. Delaunay executed several studies related to this composition, including a larger canvas that now belongs to the Honolulu Museum of Art in Hawaii along with a work on paper titled L 'Arc en ciel ll (The Rainbow II).

Delaunay previously incorporated the Eiffel Tower into several Orphist paintings; however, the present work represents Delaunay's shift away from geometric forms, towards a more expressive, colourful approach. As G. Vriesen and M. Imdahl wrote of the artist, ‘Delaunay considered the language of colour the most human language imaginable in art. Every human being he said is capable of being affected by the universal language of colours, by their play, movement, chords, rhythms—in short, by those arrangements that are especially suited to man's natural inclinations' (Robert Delaunay: Light and Colour, New York, 1967, p. 80). Arc-en-ciel no. 5 (Rainbow no. 5) exemplifies Delaunay's deeply emotive, lyrical and harmonious use of colour during this new phase of his career.