Your friend can go to the Psycom website, the 3114 website to talk about suicidal thoughts, Campus France website to find more resources.
It may happen that, when confiding in you, your friend brings up other subjects than those listed here (experience of a discriminatory situation, physical or psychological violence, threats or harassment, etc.). If this is the case, you can suggest to your friend that he or she research existing resources.
Once you have found the information, it may be difficult to make an appointment, or to wait for the first appointment (which may be several weeks or even months later). Supporting your friend and offering to accompany them through these steps can make a real difference.
If your friend refuses your offer of support, you can find out for yourself what they are going through. Don't forget to take care of yourself in all this!