It's usual to say that MPs are old people that don't understand current technologies, but in law preparation committees they appear to be well aware; in particular, they mentioned a "double-anonymity" system where the site requesting your age wouldn't know your name, and the entity serving age requests wouldn't know which site it is for. They are also aware that people walk-around age verification checks with e.g. fake ID cards, possibly AI generated.
I'm not sure if it is actually doable reliabily, and I'm not sure either that the MPs that will have to vote the law will know the topic as well as the MPs participating in these committees.
I would personally consider other options like a one-button admin config for computers/smartphones/tablets that restricts access according to age (6-14, 15-18) and requiring online service providers to announce their "rating" in HTTP headers. Hackers will certainly object that young hackers could bypass this, but like copy-protection, the mission can be considered complete when the vast majority of people are prevented from doing what they should not do.
Alternatively one could consider the creation of a top-level domain with a "code of content" (which could include things like "chat control") enforced by controlling entity. Then again, an OS-level account config button could restrict all Internet accesses to this domain.
Perhaps an national agency could simply grant a "child safe" label to operating systems that comply to this.
This type of solutions would I think also be useful in schools (e.g. school-provided devices), although they are also talking about severely limiting screen-time at school.
For the french speakers, see:
[1] https://videos.assemblee-nationale.fr/video.17950525_6942684...
[2] https://videos.assemblee-nationale.fr/video.17952051_6942761...