In essence, the French government wanted logs on a climate change activist. French officials contacted their Swiss counterparts, who then contacted Protonmail, and Protonmail immediately folded. Their ToS used to state "we don't log your IP," which has since been changed to "By default, we do not keep any IP logs which can be linked to your anonymous email account." So much for what people thought the company was.
For email, people are probably better off using TOR with CTemplar. CTemplar also keeps you off the clearnet in the process, which Protonmail failed to do.
https://techcrunch.com/2021/09/06/protonmail-logged-ip-address-of-french-activist-after-order-by-swiss-authorities/ said:ProtonMail, a hosted email service with a focus on end-to-end encrypted communications, has been facing criticism after a police report showed that French authorities managed to obtain the IP address of a French activist who was using the online service. The company has communicated widely about the incident, stating that it doesn’t log IP addresses by default and it only complies with local regulation — in that case Swiss law. While ProtonMail didn’t cooperate with French authorities, French police sent a request to Swiss police via Europol to force the company to obtain the IP address of one of its users.
The next day, @MuArF on Twitter shared an abstract of a police report detailing ProtonMail’s reply. According to @MuArF, the police report is related to the ongoing investigation against the group who occupied various premises around Place Sainte-Marthe. It says that French police received a message from Europol. That message contains details about the ProtonMail account.
Here’s what the report says:
The company PROTONMAIL informs us that the email address has been created on … The IP address linked to the account is the following: …
The device used is a … device identified with the number …