In 2019, the brown marmorated stink bug, Halyomorpha halys, had colonized more than half of the metropolitan departments in France, according to the French research organization INRAE. The insect, which grows no longer than 17 mm as an adult, was first reported in 2012 in the shared gardens of Strasbourg. Initially mistaken for a native species, Rhaphigaster nebulosa, it was officially identified as Halyomorpha halys in 2013. The bug has since become a growing concern for French agriculture and ecosystems. The spread of the insect was closely monitored through the efforts of over 4,000 citizens between 2012 and 2021. INRAE, in collaboration with the National Museum of Natural History, launched two citizen science initiatives: Agiir in 2012 and INPN-Espèces in 2016. These programs enabled real-time tracking of the bug's movement across France and contributed to a study published in Scientific Reports in 2021. A map showing the first detection year of the bug in each department from 2012 to 2021 is available on the Ephytia website of INRAE. The invasion accelerated after 2015. The first individual was recorded in Escalquens, a town in the Haute-Garonne department, on August 28, 2015, according to the DRAAF (Regional Directorate for Agriculture and Food) record. By 2018, Jean-Claude Streito, an expert on the insect at INRAE, noted over 100 reports since 2015, with the number tripling in August alone. He identified Alsace and the Paris region as the main affected areas, with a report also coming from Corsica. Thirteen years after its discovery, the bug is now found almost everywhere in France. Originating from Asia, Halyomorpha halys is found in countries such as Korea, China, Japan, and Taiwan. It spreads involuntarily with human activity, moving to Europe, Africa, and beyond. First detected in 2004 in Liechtenstein and Switzerland, it has since spread to more than 20 countries, from Portugal to Turkey and from Belgium to Italy. In 2017, it was spotted in Chile, and in 2019 in Morocco, followed by Algeria in 2021. In Australia, New Zealand, and New Caledonia, the insect has been intercepted during cargo inspections but has not yet established a population. The bug feeds on more than 120 species of both wild and cultivated plants and in France produces one to two generations per year, compared to up to six in Asia. Damages have been reported in Europe since 2015 and observed in France since 2018, mainly on fruit trees but also on vegetable crops. In winter, the insect seeks shelter in protected areas such as dry cracks, the thick bark of dead trees, or human structures, which explains its tendency to enter homes in October. According to the DRAAF Occitanie record, mass infestations do not pose a danger to humans or animals, and the bug does not bite. In 2018, Jean-Claude Streito noted that it was not possible to stop the bug's spread in Europe. In 2021, INRAE was launching a new participatory program to monitor three other potentially invasive species: the Japanese beetle, the red-banded cockroach, and the spotted lanternfly.