Good news from the SIA France.
They have problems delivering paper maps on time this year, but they offer free download of the digital version of a series of maps and guides, including the France N and France S "million" maps.
Registration to the site https://www.sia.aviation-civile.gouv.fr/ is required.
There, you can "purchase" at 0€ the right to download the maps, provided that you only use them for the original purpose, i.e. aviation.
The format is unfortunately not geolocalised TIFF, but simply PDF, so some work is required to calibrate them ad figure out how far zooming makes sense.
As I am anyway blocked at home by the sanitary measure, I am already busy testing on one of the maps.
Petr, I will inform you about the result in direct msg in case you would consider integrating some maps in FIF.
The site offers also other interesting downloads, like a phraseology manual and a series of more detailed regional maps.