This visualization displays the incidence of influenza across French regions during the 2014 season, with a choropleth map coloring each region based on its total annual case count. The map is rendered using `d3.geoConicConformal` projection and `d3.geoPath` to draw France’s departmental boundaries. Data from a CSV file is joined to a GeoJSON of regional shapes, and the final fill color reflects each region’s summed value. The code also includes a US states GeoJSON, though its use is not demonstrated in the visible implementation.