I'm the project lead for Matrix. Failing that, on the French side there's been some press where they've confirmed the system is built on Matrix & Riot (https:/

I'm the project lead for Matrix. Failing that, on the French side there's been some press where they've confirmed the system is built on Matrix & Riot (https://www.nextinpact.com/news/106463-la-france-travaille-a-messagerie-detat-chiffree-pour-cet-ete.htm https://www.nextinpact.com/news/106463-la-france-travaille-a..., although it's behind a paywall), plus others have spotted the Github repository too.