Another article, much better and presents in more detail that Olvid was audited on an older version and chosen because it was French and they applied for it (French) https://www.numerama.com/tech/1575168-pourquoi-les-ministres-vont-devoir-renoncer-a-whatsapp-signal-et-telegram.html
Google translate link original post : https://www-lepoint-fr.translate.goog/high-tech-internet/les-ministres-francais-invites-a-desinstaller-whatsapp-signal-et-telegram-29-11-2023-2545099_47.php?_x_tr_sl=fr&_x_tr_tl=en&_x_tr_hl=fr&_x_tr_pto=wapp
The translation has some mistakes but good enough to understand the context.
Here is a short summary :
Olvid passed a 35d intrusion test by Anssi (French cybersecurity state organisation) experts or designated experts, with code examination without finding any security breach. Which is not the case of all other 3 messaging apps (either because they didn’t do any test, or because they didn’t pass).
This makes WhatsApp, signal and telegram unreliable for state security.
And so government members and ministerial offices will have to use Olvid or Tchap (French state in house messaging app).
More detail in the article.
I don’t know much but what I do know is when a government endorses a secure messaging service, it’s definitely not secure.
They’re using it themselves, not forcing citizens to use it. It’s when they force citizens to use an app they claim is secure that I am distrustful. I would assume their intentions are more pure when it’s their own state security rather than their citizens’ privacy.