The first step was setting up an interview for about 30 min with HR, after that they invited me to work on a Java coding assignment and submit it to Github.
After it was submitted, a code reviewer will critique your code regarding his own pre-conceptions on what should be good or not.
I think they are very organized and detailed on almost every aspect of the process. I think in overall was a decent experience, but if you're thinking about interviewing with Picnic, take into consideration that you might be working a lot on the coding task and very probably will be rejected as there's no way to measure what is expected, even if you do a good job.