This paper investigates the environmental impact of urban road freight in the Paris region, focusing on pollutant emissions. We develop a modeling chain including a freight demand model, a multiclass traffic assignment model, and a road emission model. This allows for a detailed representation - spatially and with regard to operations - of urban road freight. We find that while urban road freight represents only 6% of trips and 8% of distances traveled by road in the Paris region, it accounts for 36% of total damages caused by pollutant emissions from road traffic. This is the combined result of light and heavy goods vehicles emitting more than private cars, and of freight traffic being more spatially concentrated (within the city center) than passenger traffic, thereby affecting more population. All in all, the environmental cost of urban road freight is around 2.1 billion € per year. Some policy implications are discussed.