This choropleth map visualizes the total number of flu cases across French administrative regions for 2014, using a blue-to-red linear color scale to indicate intensity. Hovering over a region reveals its name and total case count via a tooltip. Built with D3 v4, the map uses `d3.geoConicConformal` for the projection and `d3.geoPath` to render region boundaries from a GeoJSON file, while the data comes from a CSV sourced from a gist.