20 May 2022 By Rob Wilson. Photography by Simon Menges

The 63,500m² Morland Mixité Capitale remodels and extends the former Préfecture de Paris building, completed in 1964

Originally designed by the architects Albert Laprade, Pierre-Victor Fournier and René Fontaine and built between 1957 to 1964, Morland Mixité Capitale is located on Boulevard Morland on a former river island Île Louviers on the River Seine in the 4th arrondissement.

The existing complex originally comprised a 50m-tall, 16-storey building with an H-shaped ground plan flanked by two nine-storey wings, which once housed city administration departments. It was one of 23 existing buildings and public spaces selected for makeovers to create models of exemplar sustainable urban design under the motto ‘Réinventer Paris’.

The reworked complex now accommodates a wide spectrum of usages: both high-end and affordable housing, a hotel, youth hostel, offices, retail, gallery, food market and a childcare facility. The two upper storeys house an inhabitable art installation by Ólafur Eliasson and Sebastian Behmann from Studio Other Spaces Berlin, a bar and restaurant.

Two new building volumes have been added, designed to mediate between the scale of the existing and neighbouring buildings, which are raised above the ground to create a new public axis creating a passage from the boulevard to the River Seine. Load-bearing, vaulted arcades characterise this passage at ground floor level, intended to attract passers-by into the interior of the complex.

The existing fabric was repaired instead of being replaced wherever possible. Energy and resource consumption have been reduced through the use of heat exchange and a closed phyto-purification system for urban gardening on the roof, part of 4,000m² of green space across the whole scheme.

The project was selected to be redesigned under the ‘Réinventer Paris’ international competition, launched in November 2014 by the Paris city government looking to create a a better quality of life in the city and aimed at consortia of developers, investors, architects, planning consultants, landscape architects and artists.

The core architectural idea for the project was to preserve, renovate and further develop the existing building. This not only ensures urban continuity, but also represents the most important component for the project’s sustainability concept, which has achieved certification with a range of French and international sustainability standards.

Preserving building fabric as far as possible significantly reduces CO² emissions and saves energy in terms of demolition and disposal. With great respect for the existing building fabric, the renovation of the former Préfecture repaired all elements that were not too damaged with the aim of preserving them.

All the stone slabs of the façade were cleaned, repaired and only damaged slabs were replaced. The stone used for this, like the one originally used, comes from the Buffon quarry in Burgundy. Any alterations or additions to the façade were made for the benefit of living quality and due to legal requirements. For example, all rooms were given additional external areas through the integration of new balconies and storey-high windows.

The original steel windows no longer met the current standards for thermal insulation and were therefore replicated as aluminium windows. These changes in appearance fit into the design concept and character of Laprade’s design, developing it carefully further. Inside, modified, flexibly designed floor plans ensure that the complex can be re-used in the long term, even if there is a conversion of use in the future.

The further development from its original use as an administration building to a lively mixed-use gives the complex a second lease of life by adapting to the demands and desires of a modern city and society. The principle of flexible use is therefore continued also in the new parts of the building. With the arcades on the ground floor, the complex now has a durable, robust primary structure made of in-situ concrete that has been designed so that it can also be used for different purposes in the future. By cleverly bundling the shafts, the areas under the arches can be used as interior space as well as exterior space by adapting them with a flexible final finishing layer with little structural intervention.

The green courtyards and the roofscape serve as water reservoirs in terms of a “sponge city”. They can absorb rainwater, store it and release it when needed. The intensive planting – including urban gardening with vertically planted crops to maximise the cultivation area and minimise water consumption – binds fine particulate matter and encourages biodiversity. A closed phyto-purification system is used for irrigation, in which grey water from the hostel is treated, stored and re-used for irrigation.

The energy cycle, including heating and cooling, is designed according to the same principle: Based on heat exchange, the different uses within the project can benefit from each other. The waste heat generated in the office areas facilitates for instance the hot water supply in the hotel by connecting the systems to three heat pumps via a water circuit. This system reduces the total consumption of the building by 15 per cent below the prescribed regulations. The additional energy required is supplied by collective district heating and cooling systems. In addition, photovoltaic panels on the roofs generate energy that is used for operations. David Chipperfield Architects Berlin

Start on site 2018 Completion 2022 Gross internal floor area 63,500m² Gross site area 8,400m² Construction cost Undisclosed Architect David Chipperfield Architects Berlin Contact architect BRS-Architectes, Paris (procurement) Executive architect Calq Architecture, Paris Client Société Parisienne du Nouvel Arsenal represented by Emerige Structural engineer Somete, Paris; Bollinger & Grohmann, Berlin M&E consultant Barbanel Ingénierie, Toulouse QS CB économie, Chartres Landscape consultant Michel Desvigne Paysagiste, Paris Acoustic consultant Acoustique Vivié & Associés, Paris Fire consultant MDS, Paris Façade consultant Bollinger & Grohmann, Berlin Sustainability consultant Etamine, Paris Art installation Studio Other Spaces, Berlin (Ólafur Elíasson und Sebastian Behmann) Temporary art installation Encore Heureux, Paris Main contractor Bouygues, Paris

Tags David Chipperfield Architects mixed use Office paris Retrofit Workspace

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