Lise Meitner Square is part of the experimental housing project START in Ivry-sur-Seine, which includes five residential buildings. And yet, this square was not initially meant to exist. Its creation required overcoming major constraints linked to two 1,500-metre-deep geothermal wells on site—providing heating for a large part of the city— which originally demanded a fenced, impermeable and inaccessible zone.
Such an arrangement would have seriously compromised the quality of life for the nearly 300 families living in START-Ivry.
After long negotiations with the geothermal operator, we secured a 2,600m² public space—transforming a technical limitation into a meaningful urban asset.
Though shaped by constraints, Lise Meitner Square is ultimately a gift to the neighbourhood: a fully open, inclusive public space. It occupies a privileged location on the Seine riverfront, just 400m from the future ‘Parc-de-la-Confluence’, at the heart of the ZAC-Ivry-Confluences urban renewal zone.
The square’s design highlights the geothermal system at its centre, while its materials meet strict maintenance requirements and its colour palette aligns with the START-Ivry project. Its triangular form connects it to neighbouring public areas, while the two newly created pedestrian alleys cross the plinths of the buildings, link the square to the main avenue, and frame views toward the iconic cable bridge over the Seine.
Because of the maintenance constraints of the geothermal wells, plantings and fixed furniture were prohibited, and most of the surface had to remain waterproof and extremely robust to support heavy maintenance vehicles. Moreover, as the square was never originally planned, there was no budget allocated for its creation. However, through close collaboration with the architect of the START-Ivry project, we liberated a budget of €642,000 excl. VAT to make it possible.
From infrastructure to public space
Three main themes structured the layout and materialisation of this “miraculous” square:
1. The Geothermal Energy
The square's design, and especially its safety perimeter — usually seen as a technical constraint — becomes here the central element of the project, materialised by an orange asphalt ring tracing the emblematic oval shape of the square.
Three ground markings animate and ‘civilise’ the large black asphalt zone at the centre of the square. All three are applied with specialised asphalt paint, similar to that used for pedestrian crossings—durable, high-contrast, and suited to the square’s maintenance regime. The three ground markings are:
> A “Super-Zebra”: A continuous “zebra-cross carpet” running across the north-west sector. A simple, legible sign that underlines the space’s pedestrian character and visually links the single tower to the rest of the ensemble.
> The “Mini-masterplan”: The footprint of the iconic five buildings of START-Ivry’s massing plan, oriented like the project and set at 1:30 scale. A cue to read the plan in situ—improving legibility and reinforcing attachment for residents and passers-by.
> The “Quote”: A line by French writer and anthropologist Françoise Héritier (1933–2017), from her book « Le Sel de la vie » (2012): « Respirer l’odeur secrète du goudron et de la mer dans les cheveux de la personne qu’on aime… » (“Breathing in the secret smell of tar and sea in the hair of someone you love…”). It casts a more poetic light on the black oval.
2-The Four Paths
Two new pedestrian alleys cross the plinths of the buildings and connect the main avenue to the square. The northern alley opens up to a view of the iconic cable footbridge over the Seine. Both are paved in beige deactivated concrete, and lined with five benches along each alley, each shaped like the footprint of one of the five surrounding buildings and integrated with lighting.
A third path borders the square to the south—a 6-metre-wide strip of brushed concrete, heavy-duty and road-like in appearance. It provides maintenance and delivery access.
A fourth path, in deactivated concrete, runs along the north edge of the square, framing it against the adjacent building façade.
3-The Three “Zones”
Three circular areas are designated as flexible-use zones—for sports, fitness, café terraces, etc.—each materialised with a different treatment: red soft surface, beige deactivated concrete, and low grass.
The remaining surface is planted with mid-height grasses and perennials, forming soft borders around the circular zones. In line with geothermal constraints maintenance restrictions, planting is limited to vegetation between 50 cm and 1 m in height, depending on season.
The planting palette includes evergreen, wind-responsive grasses such as feathergrass, fescue, and hairgrass. Accents of blue come from perennial oats, and delicate green and purple spikelets punctuate the surface. These light, constantly shifting plants create a relaxing and sensorial experience throughout the square.
The wild grasses form a contemplative, blooming landscape throughout the summer, attracting bees, butterflies, birds, and small animals. This natural ecosystem is complemented by biodiversity features: piles of drilled logs, light stones, sand mounds, and bird nesting boxes designed to support various species.
The remaining surface is planted with mid-height grasses and perennials, forming soft borders around the circular zones. In line with geothermal safety restrictions, the planting is limited to vegetation between 50 cm and 1 m in height, depending on season.
The planting palette includes evergreen, wind-responsive grasses such as feathergrass, fescue, and hairgrass. Accents of blue are introduced through perennial oats, and delicate green and purple spikelets punctuate the surface.
These light, constantly shifting plants create a relaxing and sensorial experience throughout the square.
The wild grasses form a contemplative, blooming landscape throughout the summer, attracting bees, butterflies, birds, and small animals. This natural ecosystem is complemented by biodiversity features: piles of drilled logs, light stones, sand mounds, and bird nesting boxes designed to support various species.
Street furniture and Lighting
Because fixed street furniture is prohibited on the square due to geothermal constraints, the items in the heart of the block (sports equipment, chairs) are easily removable.
The sports equipment is installed in two of the circular zones. The chairs are installed on the northern part of the square, combining coloured metal (matching the project palette) and wood. Their alternating orientations create small clusters of 2–3 seats.
The geothermal wellheads, which must be protected from traffic, are surrounded by custom-made galvanised-steel guards that can also be used as supports for fitness exercises.
Two types of lighting are provided for Lise Meitner Square:
-High lighting: 5-metre masts with adjustable luminaires around the square, covering areas with a radius of approx. 20 m.
-Low lighting: 2.5-metre masts installed every 5 metres along the two alleys and the path in front of Tower 5, reinforcing the orientation of these routes.
(Note: The accompanying images illustrate the finalisation phase of the square. Mid-height planting around the circular zones is yet to be completed.)
