Following the re-emergence of the bluetongue virus serotype 8 (BTV8) in Septem-ber 2015 and in accordance with the European Commission's regulatory require-ments, a new entomological surveillance network has been set up throughout mainland France to monitor the activity of Culicoides, which are vectors of BTV. The new Culicoides surveillance network uses suction light traps that opera-te one night per week in one site per eco-climatic zone. Twenty-four eco-clima-tic zones were determined in mainland France by analyzing the data collected by the ¿rst surveillance network set up from 2009 to 2012 during the emergen-ce of BTV8. Each eco-climatic zone, regrouping one or more French departments, is homogeneous, taking into account the diversity of Culicoides species, the dura-tion of vector inactivity and the week of the beginning and the end of inactivity. This entomological surveillance active from November (Y0) to April (Y1) has made it possible to determine successfully periods without Culicoides vectors for the different eco-climatic zones defined on the continental territory. The informa-tion provided by this network, coupled with the surveillance of viral circulation, made it possible to report during winters 2015 to 2018 several French departmen-ts in BTV seasonally free zones, thus lifting restrictions on livestock movements. Research impact highlights: Following the re-emergence of BTV8 in September 2015, a new Culicoides surveillance network is operational throughout mainland France to determine the periods without vectors in each eco-climatic zone. The information pro-vided by this network, coupled with viral circulation monitoring, allows BTV's seasonal free zones to be declared each winter, thus lifting restrictions on livestock movements.