While renovating the landmarked Landtag (state parliament) in Baden-Württemberg — the first construction of a parliament building in Europe after the Second World War — the plenary hall is to be naturally lit and opened up to the adjacent foyer. The building captivates with its uncompromising modern design: behind a large format glazed facade there are open spaces that contrast the introverted plenary hall in the middle of the building. The challenge was to reconcile the desire for improved working conditions with the spatial dramaturgy of the building. Therefore, the glazed openings in the hall walls were placed so that the contrast between the approximately square building with its office zones and the nine-sided hall is preserved. The daylight ceiling in the plenary hall results in an entirely new spatial impression In consideration of the ceiling’s load-bearing behaviour, the plenary hall is made brighter through small openings in the roof plane. Interspersed conical openings enable a direct view to the sky. As a reminder of the old hall, the geometry and proportions of the original wood panelling were adopted in the design of the new surfaces. In order to achieve effective protection from the sun — while at the same time maintaining the exterior impression of the façade — the office zones received a second, interior glass facade, which can be shaded by blinds in the space between the two facades.