This research focuses on defining a post-war British urban planning tradition and its transmission to France in the context of the construction of new towns. The first part of my thesis seeks to outline the contours of this tradition. I use the term ‘tradition’ to refer to a coherent body of know-how, methods and operational concepts, commonly used by a group of professionals and partially codified. The period under consideration spans some thirty years, from around 1940 to 1970.

The key players belong primarily to two major public institutions, acting as both project owners, planners and builders: the London County Council’s Department of Architecture, responsible, in particular, for drawing up the 1943 London Plan and its implementation in the British context; and the IAURP, responsible for the creation of new towns in the Paris region in the French context. I analyse the urban planning practices of officials from these two institutions, their use of urban concepts, the planning mechanisms and methodological approaches they implement.

The thesis is structured in two parts: the first defines these urban planning concepts within the British context and examines how they were put into practice and formalised; the second analyses their reception and adaptation within the French context, as well as the motivations of the key players involved.

The aim of this thesis is to examine the processes of densification in predominantly detached-house neighbourhoods within suburban and peri-urban areas, which have so far received little attention in terms of their morphological transformations. To this end, we adopt an approach rooted in the political economy of urban production, which seeks to examine jointly the political, economic and social aspects, as well as the regulatory and technical factors, that may explain the material reality of the urban transformations observed. In this regard, we bring together two strands of research: work on territorial political economy and work on the economics of spatial planning. More specifically, the concept of post-suburbanisation—understood as a widespread process of intensive development that affects suburban areas in different ways and leads to the gradual autonomy of these suburbs from the central city of the conurbation—is at the heart of our approach.

Post-suburbanisation differs from suburbanisation, which was based primarily on extensive urban development. It therefore raises the question of densifying the low-density residential areas inherited from the suburban era. However, not all local authorities are seeking to densify; some deliberately prevent densification, whilst others, on the contrary, seek to encourage it. This leads us to formulate the central hypothesis of our work, namely that there is a link between a local authority’s post-suburban strategy and the preferred form of densification.
We have studied densification processes in predominantly detached-house neighbourhoods, in contexts characterised, amongst other things, by the existence of explicit local densification policies, in two municipalities in the Toronto metropolitan area in Canada (Guelph and Markham) and in two municipalities in the Paris region in France (Magny-les-Hameaux and Noisy-le-Grand). A comparison of the four case studies reveals two main types of densification processes: soft densification processes (Guelph and Magny-les-Hameaux), characterised by densification without a change in urban form; and strong densification processes (Markham and Noisy-le-Grand), characterised by a significant alteration of the urban form that may lead to the replacement of all or part of the pre-existing detached housing stock with apartment blocks. This is our first finding.

A detailed analysis of contextual processes and the various policies specifically aimed at densification reveals a second finding: in all four municipalities, the stated densification policies are explicitly linked to a pursuit of relative centrality. The form of densification observed within predominantly suburban areas thus appears both as a means and as a result of the degree of centrality sought by a given municipality within the post-suburban hierarchy. More specifically, in the cases studied, incentive-based policies for gentle densification are implemented in municipalities adopting a strategy of centrality with a largely local scope, which translates into a policy of moderate, mainly residential growth. Whereas strong densification policies (whether incentive-based or interventionist) are the preserve of municipalities adopting a sub-regional centrality strategy, which translates into entrepreneurial-style policies aimed at attracting households and jobs to their territory. This research also shows that whilst densification processes result mainly from market mechanisms that manifest themselves differently depending on the national urban and cultural context, the policies implemented play an important role in the creation of these land and property markets.

Finally, we identify four types of local policies aimed at increasing the density of predominantly suburban areas: incentive-based policies for gentle densification, incentive-based policies for intensive densification, interventionist policies for intensive densification, and interventionist policies for gentle densification. These different types of policies influence, in distinct ways, the form (resulting urban forms) and configuration (stakeholders involved, stakeholders affected, distribution of capital gains) of densification processes.

Coworking spaces are workspaces shared by individuals from various
organisations within an open-plan environment. This thesis analyses the development of the coworking
market in the Île-de-France region in relation to the ways in which work is carried out in these spaces. The role of physical proximity in the development of collaborative practices is examined in a Parisian coworking space. The study of the intersections between commercial and non-commercial exchanges demonstrates that reciprocal effects help to strengthen the bonds between coworkers.

Coworking spaces can facilitate entrepreneurial projects through peer learning and access to shared resources within the space. However, this requires coworking managers to organise collaboration and make it visible. They transform coworking into a new form of property service that combines physical space with an informal service for connecting workers. The value of coworking spaces is therefore co-created by the users.

This thesis also examines the development of coworking in the Île-de-France region in the context of a range of public policies. Local authorities helped to shape the market before property developers brought about a shift in scale within the very concept of coworking. The coworking operator has become an intermediary enabling the pooling of office demand from small businesses in metropolitan areas, and has come to occupy a place within the property value chain.

Members of the jury

• Didier Paris, Professor, University of Lille 1
• Antoine Picon, Research Director at École des Ponts ParisTech (PhD supervisor)
• Raphael Suire, Professor, University of Nantes (Rapporteur)
• Pierre Veltz, Professor Emeritus at École des Ponts ParisTech
• Elsa Vivant, Senior Lecturer, Université Paris-Est (Joint thesis supervisor)
• Sharon Zukin, Professor, Brooklyn College, City University of New York (Rapporteur)
• David Cocheton, Director of Planning, SEM Plaine Commune Développement (Guest)

This thesis aims to re-examine the concept of reconstruction following the Fukushima nuclear disaster in March 2011. By examining the reconstruction policy launched by the Japanese authorities in the wake of this disaster—despite the health risks posed by low levels of radiation persisting in the environment—it explores the socio-cultural consequences of this policy on those affected, whether they leave, remain or return to the contaminated areas. What form should reconstruction take following this nuclear disaster? What form should reconstruction take in contaminated areas, for populations affected by this disaster and facing this long-term health and environmental risk?

To address these questions, this thesis first analyses the Fukushima disaster in three phases – before, during and after the event – and the management of this disaster at two levels – collective and individual. It also examines the socio-technical controversies surrounding the risk posed by low doses of radiation – a risk that extends over a wide area and a long period of time – thereby enabling us to grasp the complexity of this ‘post-accident’ situation in a nuclearised Japanese society.

Secondly, this thesis conducts a comparative study of the Minamata disaster, caused by mercury contamination dating back to the 1930s. By analysing these two case studies in their various dimensions – uncertainty, risk and the onset of the disaster – it highlights the process of reconstruction, or even rebirth, of a Japanese society repeatedly affected by techno-industrial disasters, a mirror image of the country’s development and modernisation.

Members of the jury

• Claudine Burton-Jeangros, Professor, University of Geneva (Rapporteur)
• Sophie Houdart, Research Director, CNRS LESC (Rapporteur)
• Paul Jobin, Associate Research Fellow, Academia Sinica (PhD supervisor)
• Valérie November, Research Director, CNRS (PhD supervisor)
• Philippe Pelletier, Professor, University of Lyon 2 (Examiner)
• Sandrine Revet, Research Director, CERI, Sciences Po (Examiner)
• Sezin Topçu, Research Fellow, CNRS CEMS-EHESS (Examiner)

How do different state structures and urban and energy socio-material contexts explain the uneven
diffusion of district energy systems (DES) in urban areas of France and Alberta between 2000 and 2014?

To answer this question, this thesis analyses the processes inherent to low-carbon energy transitions
through socio-spatial and socio-material lenses, considering power relations and state structure. At the
intersection of urban planning and energy systems, DES proves practical to explore the nexus between
low-carbon governance, energy governance, and urban governance.

Theoretical frameworks employed in the analysis include :
1) recent contributions from (urban) transition studies and socio-technical systems;
2) a Lefebvrian conceptualisation of socio-space and social changes;
3) Jessop’s (1990, 2008) strategicrelational approach of state power.

An original inter-scale comparative research allows for examining the uneven construction of low-carbon energy policies in France and Alberta, and their relations with state structures, and existing urban and energy systems. Jessop et al.’s Territory-Place-Scale-Network (TPSN) framework is mobilised to overcome the issues of commensurability and spontaneous comparison.

This theoretical and methodological approaches provide a robust demonstration that the provincial scale in Canada, and the national scale in France, are the scales dominating the construction of low-carbon energy transitions and urban governance. Despite similar state powers, French and Albertan governments
developed different state policies on low-carbon transition, highlighting selectivity in the exercise of state
capacities.

They differently engaged and enabled local urban governments and developed different state
interventions on DES. In France, state-sponsored DES activated new channels of growth compatible with
existing dominant socio-materialities; in Alberta, state-funded DES experiments failed to activate new
channels of growth compatible with dominant socio-materialities. This thesis posits that selective
construction of low-carbon policies depends on the material interests of dominant energy and state actors.

In other words, the state does not seek to reduce greenhouse gas emissions by all means. Rather, it seeks
to reproduce dominant socio-material status quo, adapting low-carbon policies to existing socio-material
configuration. Ultimately, this thesis validates how the concepts of state structure and the TPSN framework can enrich the theorisation of space and power relations for (urban) transition studies.

Members of the Examination Committee

• Julia Affolderbach, Senior Lecturer, University of Hull, United Kingdom, Examiner
• Sophie Van Neste, Professor, Institut national de la recherche scientifique (INRS), Montreal, Canada, Examiner
• Olivier Coutard, CNRS Research Director, LATTS, Université Paris-Est, Co-supervisor
• Noel Keough, Professor, University of Calgary, examiner
• Byron Miller, Professor, University of Calgary, Canada, co-supervisor
• Jonathan Rutherford, Research Fellow (ENPC), LATTS, Université Paris-Est, examiner.