I applied through university. The process took 1 day. I interviewed at EPFL (Lausanne) in Sept 2018
Interview
I had to reach a good grade in the course first. Afterwards the professor asked me to pass by his office to discuss the details. During the discussion he proposed all benefits I could gather from this possibility. He seemed very motivated to hire me.
I applied through university. The process took 4 weeks. I interviewed at EPFL in Aug 2019
Interview
Pour passer l'entretient il suffit de connaitre le professeur et avoir eu plus de 5 dans la matière concernée. Je conseille d'envoyer un mail avant la fin des cours du semestre précédent et ne pas attendre les mails de demande d'assistants étudiants