France air quality map

This is what I was able to figure out, there are multiple different sites all with different top level domains.

The indicator is called L’indice ATMO.

Map

There's a high-level map at

https://www.atmo-france.org/

and a more detailed map at

https://www.atmo-france.org/indiceatmo

L'indice ATMO

The colour scale goes from light blue (cyan) to purple.

Scale from L'indice ATMO - Quels sont les polluants pris en compte ?

Levels are in micrograms per cubic metre µg/m³ .
Note that PM2.5 and PM10 have different thresholds for each level.

Regional Associations

Data for the map are drawn from many regional associations, which have their own websites (and sometimes their own maps and data download).

Les Associations Agréées Surveillance Qualité de l'Air - AASQA
https://www.lcsqa.org/fr/aasqa

Country-wide Alerts

« Carte des épisodes de pollution »

https://www.lcsqa.org/fr/vigilance-atmospherique/episodes/carte

Note this is using an alert scale, coloured from grey to red; it's not the same scale or colours as the indice ATMO.

Data

Data is available from multiple different sites, including the national Atmo France site, where you search the map for available datasets

https://map.atmo-france.org/

and I guess a site called Geodair (stylised GeO D'air) ?, although I have to say their map doesn't accord with the main Atmo France map

https://www.geodair.fr/donnees/consultation

Individual regional air quality association websites also often have data download options.