Ruthenium 106 has been detected in late September by several European networks involved in the monitoring of atmospheric radioactive contamination, at levels of a few milliBecquerels per cubic meter of air. IRSN's investigations make it possible to provide information on the possible location of the source of the release as well as the order of magnitude of the quantities released. As soon as it became aware of the first detections of Ruthenium 106 in the atmosphere in Europe, IRSN mobilized all its means of radiological monitoring of the atmosphere and conducted regular analysis of the filters from its monitoring stations. For the period from September 27 to October 13, 2017, only the stations of Seyne-sur-Mer, Nice and Ajaccio revealed the presence of Ruthenium 106 in trace amounts. Since October 13, 2017, Ruthenium 106 is no longer detected in France.