The French article mentions:
Why was he under threat of a search warrant?
The Justice considers that the absence of moderation, cooperation with law enforcement and the tools offered by Telegram (disposable numbers, cryptocurrencies...) makes him an accomplice to drug trafficking, child-crime offenses and swindling.
Or does it refer to public channels only?
No, not yet.
> Or does it refer to public channels only?
On Telegram channels and groups are not E2EE. I'd assume that's were most of the crap is spread.
Having said that I am no fan of installing law enforcement inside private companies. However, telegrams noncompliance with court orders is problematic particularly related to protecting human rights of 3rd parties in the digital age.
You can get a warrant (a court order) to open a piece of mail, and the USPS isn't going to refuse to hand it over.
[technically they could, but someone would get stuck with contempt of court charges]
It's however a very very very slippery slope to prosecute someone for providing the tools to hold encrypted communication, just because this is also used by criminals. A lot of privacy oriented services would probably have to exit France if this holds up
The problems is the huge telegram channels spreading hacks and illicite tricks.
There is no such threats against Signal which is way more privacy oriented. (except for some new laws in UK where Signal said if they are applied, they would withdraw from the UK market:https://fortune.com/2023/07/13/signal-president-mass-surveil...
On the other hand Pavel Durov is "homeless". He is like a normal citizen.
(From the reuters link)