diff --git a/game/views.py b/game/views.py
index 9ee29ca..d5f3b7d 100644
--- a/game/views.py
+++ b/game/views.py
@@ -139,19 +139,24 @@ class GroupAddMemberView(MemberFilterMixin, SingleObjectMixin, View):
         group = self.get_object()
         if not group.is_leader(request.user):
             raise PermissionDenied()
-        username = request.POST.get("username")
-        user = User.objects.get(username=username)
-        if user == group.owner:
-            messages.add_message(
-                request, messages.WARNING, f"{user} est le propriétaire du groupe."
-            )
-            return redirect(group)
-        if user in group.members.all():
-            messages.add_message(
-                request, messages.WARNING, f"{user} est déjà membre du groupe."
-            )
+        usernames = request.POST.get("username")
+        for username in usernames.split():
+            user = User.objects.filter(username=username).first()
+            if not user:
+                messages.add_message(
+                    request, messages.ERROR, f"{username} n'existe pas."
+                )
+            elif user == group.owner:
+                messages.add_message(
+                    request, messages.WARNING, f"{user} est le propriétaire du groupe."
+                )
+            elif user in group.members.all():
+                messages.add_message(
+                    request, messages.WARNING, f"{user} est déjà membre du groupe."
+                )
+            else:
+                group.members.add(user)
 
-        group.members.add(user)
         return redirect(group)