We evaluate the impact of the rent control regulation implemented by the city of Paris since July 2019 on the rental market. We take advantage of the mass of data available in real time on SeLoger platform with the ads published by professional realtors, with a database of 422,874 observations from January 1, 2018, to July 31, 2022. We apply a differencein-differences model, where control units are located in eight major French cities in which the rental market is particularly tense but not regulated during the period of analysis. We show that the rent control policy decreased rents by 3.2% in Paris on average but that the policy is heterogeneous depending on dwelling characteristics. In particular, we find that small apartments are more affected by the policy than others.