Building on the exogenous shock linked with the first COVID-19 lockdown in France (March-May 2020), we propose an original approach relying on econometric modelling to estimate the impacts of road freight transport on the concentration of NO2, NOx and PM10 in Paris. We argue that this shock led to a significant change in the composition of road traffic, with an increase in the relative share of freight vehicles with respect to passenger cars, due to the combined exodus of numerous inhabitants, the prohibition of non-mandatory trips and the promotion of home-deliveries. As light-duty vehicles and trucks pollute more than passenger cars, we hypothesize that it led to a rise in the average emissions of pollutants per kilometer traveled in Paris. We confirm this assumption by applying a simple econometric analysis to a rich dataset containing hourly pollutant concentrations and hourly traffic flows recorded in various locations of the French capital city. Relying on the econometric results and on additional back-of-theenvelope computations, we propose tentative estimates of the health impacts of road freight transport. As compared to a counterfactual in which freight traffic in Paris would have declined in the same proportion as cars during the sanitary crisis, hence resulting in a larger decrease in pollutants concentrations, we conclude that around 7 lives have been lost. Crossing this estimate with the official value of statistical life in France, our central scenario approximates at 0.20 euro/km the excess external cost of the local pollution emitted by freight vehicles as compared to cars.