This project involves the conversion and new conception of a six-storey office building from the sixties. The building is located in Luxembourg’s city centre and is part of a perimeter block development. The two basement floors provide room for 20 parking spaces, which can be accessed via a parking lift on Rue Schiller. The existing cubature and floor heights of the former office building had to be retained in compliance with city building regulations. Other than the concrete frame, i.e. the columns and floors, however, there is nothing left of the former building structure. A complete energy overhaul of the structure and a comprehensive renovation of the south-east glass façade and the north-west natural stone façade facing the inner block was thus able to be carried out. The street façade features aluminium and glass and functions according to the box-type window principle, each office unit being equipped with narrow ventilation shutters. Since the final occupant was not known at the beginning of the planning phase, to ensure maximum flexibility, the decision was made to move the vertical access, i.e. the staircases, lift shafts, toilet facilities, corridors and equipment rooms, to the core of the building. The future offices are provided with ample natural light through the extensive glazing. The office floors can be divided into individual or open-plan office spaces. The two left basement floors, which previously housed the equipment rooms, have been converted into underground car parks providing 16 parking spaces, with direct access via a parking lift on Rue Schiller in Luxembourg-city.