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

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.