First I had a quick talk (~15 minutes) with a person from HR just to make sure the position was matching my skills and that I was still interested in the offer.
Afterwards we planned a technical phone screen which was 1 hour long and fairly easy. (Hackerrank easy exercices).
After passing the TPS I had my 3 final interviews planned, 1 was about backend coding, another about data structures and algorithms, and last one was an interview with a manager.
The coding backend was really easy, but I failed hard because I didn't really understand what I was asked at first, and the question seemed really vague, also the audio quality didn't help.
The data structure and algorithm was much harder in my opinion, but luckily for me, I had already met that problem before (which I mentioned to the interviewer). This one went ok, even though I ran short on time since we spoke longer than usual on my background at the beginning of the interview. I wasn't really expecting that coding problem for an internship interview.
The interview with the manager went well, he was really nice and seemed interested in my background, and was really willing to give accurate answers to my questions on the company.
In the end I didn't get the internship because I failed the backend interview, but overall the interview process was really good : the HR person who was in touch with me was really nice and provided me a lot of details on the interview process as well as resources to prepare.
I also got quick responses after the interviews (I got the email saying that I passed the TPS only 1 hour after the end of the interview, and a phone call only 3 days after the final interview).
Finally, they always gave me feedback after each interview, telling me what I could have improved, and why I got rejected, which is very nice from them.
Very good experience overall.