[obelus]

Proton responded to this in 2021: https://proton.me/blog/climate-activist-arrest

"the identity and location of the activist was already known to the French authorities. The fact that Proton Mail was not able to hand over any messages even under legal order proves that our encryption works, and very likely of great assistance to the activist in this case. Had they been using any other email provider, the outcome would have been very different.

"we also provide an onion site for anonymous access (we are one of the only email providers that supports this)."

They also updated the blog: "Update: In October 2021, Proton won a Swiss court ruling that email services are not telecommunications providers. Consequently, email services are not subject to the data retention requirements imposed on telecommunications providers and are exempted from handing over certain user data in response to Swiss legal orders."