Research

Denser cities are more productive, but they also generate more local air pollution. This pollution lowers local amenities, which should raise real wages as compensation, but also labour productivity, which should lower them. This paper studies how these two channels shape wage and housing price differences across French cities. To do so, I develop a spatial equilibrium model in which local air pollution is generated by city population and surface area, and lowers both local amenities and labour productivity. I take it to French data over 2002-2018, using historical, geological and atmospheric instruments to estimate the urban wage and housing cost premia that separate the two channels. I find that air pollution generated by urban density lowers wages by more than housing costs, so that real wages decrease: the productivity channel dominates. As the densest cities are also the most polluted, air pollution compresses nominal wage differences across cities, but widens real wage differences. The cost of density-generated air pollution thus lies in the existing stock of density rather than in its flow. In the main counterfactual exercise, continuing current population trends while preventing cities from expanding into space, as under no net land take objectives, barely raises air pollution, and mainly raises housing prices. Reducing the elasticity of air pollution to density by a quarter would turn the resulting real wage losses into gains.

AYEW Job Talk Session in Environmental Economics (Warwick-Monash, online, Oct 2026), ERUDITE Seminar (UPEC, Jan 2026), PPCR Workshop (ENS Lyon, Dec 2025), EAYE Annual Meeting (King's College London, May 2025), INSEE-CGDD Workshop (French Treasury, Feb 2025), GY500 Seminar (LSE, Nov 2024), UEA Meeting (Copenhagen, June 2024), Workshop on Cities and the Environment (PSE, Jan 2024), EEA Meeting (Barcelona, Aug 2023), EAERE Conference (Cyprus, June 2023), AFSE Congress (SciencesPo Paris, June 2023), JMA (Strasbourg, June 2023), Doctorissimes (Paris 1, April 2023)

We study the welfare effects of public transport infrastructure investments in the Paris region, highlighting the role of local air quality improvements typically omitted by standard quantitative urban models (QUMs). We first provide reduced-form evidence that tramway expansions improve local air quality. We then develop a QUM with endogenous worker and firm location choice, transport mode choice, and local air pollution affecting amenities and productivity. Applying the model to the Grand Paris Express metro project, we find welfare gains of around 1.5%. We show that omitting the air quality channel leads to a severe underestimation of welfare gains and spatial skill sorting, given the substantial heterogeneity in pollution exposure and in its valuation across skill groups.

WCERE (Nova SBE, Jul 2026), Meeting on Transport Economics and Infrastructure (IEB, Jan 2026), Scientific Committee of Société des Grands Projets (Paris, Dec 2025), CREST Urban and Spatial Economics PhD Workshop (Dec 2025, by co-author), AFET Conference (Lyon 2, Nov 2025, by co-author), EEA Meeting (Bordeaux, Aug 2025)

Exposure to fine particulate matter (PM_2.5) is uneven across socio-demographic characteristics. I document that phenomenon in France, and quantify the effects of a recent policy in addressing pollution levels and that exposure gap. Within cities, poorer and immigrant-dense neighbourhoods are substantially overexposed to PM_2.5. These disparities persist between 2006 and 2018 despite a 25% decline in average pollution, in contrast with the United States, where income and racial exposure gaps have narrowed. To evaluate the role of public policies in this stagnation, I exploit the staggered adoption of new city-level air quality plans in a difference-in-differences framework. The plans account for roughly 30% of the observed decline in PM_2.5, but differential improvements are too small to narrow exposure gaps. Measures targeting the industrial and residential sectors yield the largest reductions in immigrant-dense neighbourhoods, but measures targeting agriculture benefit rural areas with the fewest immigrants, such that the two effects broadly offset. Additional funding from the national government substantially enhances policy effectiveness, highlighting the importance of its support in the context of a decentralised policy.

Workshop on Air Pollution Economics (UPEC, Sept 2026), AFSE Congress (Nantes, June 2026), Discrimination and Diversity Workshop (Exeter, online, June 2025), LOCUS-REGARDS Seminar (Reims, Nov 2022), TEPP Conference (Evry, Oct 2021), FAERE Conference (Grenoble, Sept 2021)

Farm consolidation has profoundly transformed agriculture in developed countries, yet its economic and environmental consequences remain insufficiently understood. This project aims to estimate the causal effects of increases in farm size on agricultural performance and environmental outcomes in France. The analysis relies on an instrumental-variable strategy exploiting plausibly exogenous sources of variation in local farm consolidation. Combining panel data on agricultural, economic, and environmental indicators, we investigate how changes in farm structure affect productivity and pesticide use.