Light & Engineering Vol. 23, No. 1, pp. 25-28, 2015 Svetotekhnika No. 4, 2014, pp. 70-72 A LIGHT TRAP IN THE LOBBY OF THE EQHO TOWER IN PARIS LA DЙFENSE Roger Narboni and Virginie Nicolas Concepto studio E-mail: Narboni.concepto@wanadoo.fr ABSTRACT The paper is devoted to the short description of the light design part of skyscraper modernisation project in Paris La Dйfense. <...> Keywords: solar light trap, tower “Eqho”, lobby, natural light, sun’s rays Built in 1988 in the business district of La Dйfense in Paris, this 130-metre high-rise, originally called the Descartes Tower, Fig.1, underwent a renewal of its faзades and a complete restructuring of its lobby in 2011 to allow for the entry of natural light and to open it up visually to the bridge-type structure supporting the tower. <...> A SOLAR LIGHT TRAP THAT ADDS COLOUR AND MARKS THE PASSAGE OF TIME In addition to wide openings out into its urban environment, the lobby has a large glass roof 12 metres above fl oor level. <...> It is suffused in natural light, which changes the space as time goes by, throughout the days and seasons. <...> At certain times of the year, and depending on the sun’s course, sunbeams shine into the lobby beneath the bridge-type structure, projecting onto the walls and fl oor the shadowy spans of the metal mesh like structure above. <...> To breathe life into these projected lights, to highlight the size of the lobby and reveal the sun’s courses in the changing seasons, a glass installation, consisting of coloured tinted dichroic glass (integrated directly into the laminated panels in the glass roof) and refl ective panels made of mirrorFig.1. “Eqho” tower in Paris La Dйfense 25 Light & Engineering Vol. 23, No. 1 Fig.2. <...> Principle of refl ection / transparency / refraction of the various glass elements – Prototype for the glass roof Fig.3. <...> Left to right: system of vertical mirrored panels – Direct coloured projections – Deformation of the light by the mirrored panels on the mezzanine Fig.4. <...> An analytical summary of the heliodon on the glass roof determined the positioning of the glass panels 26 Light & Engineering Vol. 23, No. 1 Fig.5. <...> Installation of fl oodlights above the glass roof – Pastel shades on the ground fl oor, in the lobby <...>