The spread of SARS-CoV-2 and the resulting disease Covid-19 has killed over 2 million people as of January 22 , 2021 . We have designed a model and used it to quantify the effect of a 6 p.m curfew on the SARS-CoV-2 epidemic in Toulouse, France . The data show that this measure can lead to the opposite effect from that intended due to larger groups of people on the authorized hours.