Interchange brings the drama to Paris's new suburban orbital metro

Back in 2007, in what seems like another world – one where Muammar Gaddafi was still president of Libya, Brexit was not a referendum issue, and architects’ expertise was taken seriously by governments – the then French president Nicolas Sarkozy announced the appointment of a think-tank to come up with ideas for the future of Paris and its hinterland.

As competition between global megalopolises heated up, he felt that Europe’s largest city in terms of population – the Paris region currently counts around 12.4 million inhabitants – needed to prepare and adapt in order to fulfil France’s ambitions on the world stage. Among the decisions his government took in the wake of the consultation, whose conclusions were published in 2009, two in particular stand out: turning the Plateau de Saclay into a science superhub, and building a new orbital metro out in the suburbs.

Fifteen or so years later, a whole slew of research-institute buildings has sprouted to accommodate the elite engineering and technology schools concentrated in Saclay, and the Grand Paris Express, as the 200km-long metro is now called, is at last becoming a reality. Among the places it will serve is Saclay itself, alongside a host of other suburban destinations that never imagined being linked into what for much of its history was a strictly Parisian network. 

The €36 billion operation (that’s the current estimate – chances are the figure will hit €50 billion if and when all the lines complete, sometime in the 2030s) is a transport revolution for a city that formerly forced its banlieusards into the centre if they sought to travel from suburb to suburb, and its consequences for real-estate prices and settlement patterns will surely be enormous.

A building with neither facade nor walls?

Scheduled to come into service next year, Line 15 will be the most heavily used of the four that are planned, since it circles through the petite couronne, as the nearest ring of suburbs is known. Extensions to existing lines will link it to the current network, among them the expanded no. 14, which since last year’s Olympics connects Saint-Denis in the north to Orly Airport in the south. On that trajectory is the southern suburb of Villejuif, where a brand-new interchange opened just this January.

Named Villejuif-Gustave Roussy, the station is located in the middle of a new public plaza between the Institut Gustave Roussy – a hospital specialising in cancer treatment – and the Parc des Hautes-Bruyères. Its architect, Dominique Perrault, who in 2015 achieved ‘immortal’ status following his induction into France’s prestigious Académie des Beaux-Arts, was one of the participants in Sarkozy's 2007 think-tank. 

Although it doesn’t appear so when viewed from the plaza, the new station is a colossal effort of civil engineering, expected to handle 100,000 train-changing commuters daily when Line 15 opens. As he shows journalists around, Perrault boasts that his building has neither facade nor walls, a slightly exaggerated claim that nonetheless highlights the exceptional nature of this undertaking.

A concept image produced by Perrault’s office, DPA, illustrates the point well. It depicts a section through the Roman Pantheon buried below ground, the oculus at the apex of its dome forming a well that descends into the underworld, while in the background we see the shadowy form of the Institut Gustave Roussy. Actually rather bigger than the Pantheon (whose height and diameter are both 43.3m), the station at Villejuif takes the form of a subterranean concrete cylinder – the form that uses least material, explains Perrault – that measures 50m deep and 70m in diameter, and whose retaining walls are one metre thick. 

Lined with technical spaces and, on its upper levels, retail outlets, the well descends to where Lines 14 and 15 cross, the former suspended above the latter, each traversing the space in its own rectangular-profile concrete tube, which contains platforms as well as tracks. To get passengers down to the interchange, a battery of escalators departs into the 30m-diameter central void, making for a daily commuter procession of truly Piranesian drama.

Stainless steel theatrics and internal 'starshine'

The theatricality is augmented by the finishes, which in addition to raw concrete include stainless steel treated in a variety of ways: perforated (for acoustics), satin smooth, mirror-polished, and, in what has been a Perrault speciality ever since his 1995 Bibliothèque Nationale de France, woven into mesh (also good for acoustics). 

Designed by his partner at DPA, Gaëlle Lauriot-Prévost, who also authored the tough industrial-style lighting fixtures that proliferate throughout the station, the interior surfaces help reflect both day- and electric light right to the bottom of the well, where passengers can also enjoy a little ‘starshine’ in the form of the ceiling-mounted artwork Cadran solaire. Dreamed up by the Chilean artist Iván Navarro and featuring Dibond mirrors and yellow-tinted LEDs, it brings the firmament down into the underworld by spelling out the names of a host of heavenly bodies. Navarro’s piece is just one of many art interventions planned for the Grand Paris Express, since commissions are being sought for all 68 new stations.

In addition to having ‘no walls and no facade’, Perrault’s building is open to the air, which avoids the need for mechanical smoke extraction in the central void. Nor is that part of the station heated or cooled, since the thermal inertia of the surrounding earth helps maintain relatively stable temperatures – warmer than outside in winter, and cooler in summer. Hovering above the void at grade, a lightweight folded ETFE (ethylene tetrafluoroethylene) roof keeps most precipitation at bay, its bicycle-wheel structure comprising a perimeter ring of steel and a central steel ‘eye’, between which cables and slender tie beams are stretched. 

When approached from the plaza, the station resembles a candidate for the Serpentine Pavilion, a one-storey structure comprising halos of metal-mesh brise-soleils suspended high on steel poles. Between the brise-soleils and the ETFE bicycle wheel, a band of metal gates and steel-and-glass retail pavilions delimits the boundaries of the station proper. 

Or perhaps we should say the threshold of the local shopping centre, as that is the station’s other role, the upper part being free for all to access during operating hours, since turnstiles are not encountered until level -2. Symbol of a neighbourhood undergoing transformation, the shops are aimed at the users of the many new buildings that rose in the station’s immediate vicinity in anticipation of its inauguration.

'Priceless' infrastructure – and source of resentment

Nobody, least of all Perrault, is able to say how much this truly impressive project cost. ‘Too complicated to calculate,’ replies the architect dismissively when asked during the press visit. 

Back in 2018, local rag Le Parisien put the estimate at €250 million, a pre-Covid figure that has surely risen considerably since. Inevitably, the concentration of investment represented by the Grand Paris Express has caused resentment elsewhere in France, where transport infrastructure is often chronically underfunded – for some, the pharaonic démesure of the station at Villejuif-Gustave Roussy seems to encapsulate the Jacobin arrogance of the country’s leaders. 

Meanwhile, for Franciliens (as inhabitants of the Paris region are known), it may also prove an ambiguous symbol, for the image of thousands of workers being whooshed up from the bowels of the earth into retail heaven seems uncannily like the final scenes in Fritz Lang’s soon-to-be-centenarian Metropolis.

In numbers

• Site surface area 7,500m²
• Project surface area 15,364m²
• Built volume 203,771m³
• Depth of Line 15 platforms 49m
• Depth of Line 14 platforms 37m

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