diff --git a/musician/models.py b/musician/models.py
index 3c86283..ffd594e 100644
--- a/musician/models.py
+++ b/musician/models.py
@@ -129,6 +129,10 @@ class UserAccount(OrchestraModel):
 
         return super().new_from_json(data=data, billing=billing, language=language, last_login=last_login)
 
+    def allowed_resources(self, resource):
+        allowed_by_type = musician_settings.ALLOWED_RESOURCES[self.type]
+        return allowed_by_type[resource]
+
 
 class DatabaseUser(OrchestraModel):
     api_name = 'databaseusers'
diff --git a/musician/templates/musician/mailbox_form.html b/musician/templates/musician/mailbox_form.html
index bafff86..b7484bc 100644
--- a/musician/templates/musician/mailbox_form.html
+++ b/musician/templates/musician/mailbox_form.html
@@ -4,6 +4,15 @@
 {% block content %}
 <h1 class="service-name">{{ service.verbose_name }}</h1>
 
+{% if extra_mailbox %}
+<div class="alert alert-warning alert-dismissible fade show" role="alert">
+  <strong>{% trans "Warning!" %}</strong> {% trans "You have reached the limit of mailboxes of your subscription so <strong>extra fees</strong> may apply." %}
+  <button type="button" class="close" data-dismiss="alert" aria-label="{% trans 'Close' %}">
+    <span aria-hidden="true">&times;</span>
+  </button>
+</div>
+{% endif %}
+
 <form method="post">
   {% csrf_token %}
   {% bootstrap_form form %}
diff --git a/musician/views.py b/musician/views.py
index 487434f..a6e2542 100644
--- a/musician/views.py
+++ b/musician/views.py
@@ -325,7 +325,18 @@ class MailboxCreateView(CustomContextMixin, UserTokenRequiredMixin, FormView):
     template_name = "musician/mailbox_form.html"
     form_class = MailboxCreateForm
     success_url = reverse_lazy("musician:mailbox-list")
-    extra_context = {'service': service_class}
+
+    def get_context_data(self, **kwargs):
+        context = super().get_context_data(**kwargs)
+        context.update({
+            'extra_mailbox': self.is_extra_mailbox(context['profile']),
+            'service': self.service_class,
+        })
+        return context
+
+    def is_extra_mailbox(self, profile):
+        number_of_mailboxes = len(self.orchestra.retrieve_mailbox_list())
+        return number_of_mailboxes >= profile.allowed_resources('mailbox')
 
     def form_valid(self, form):
         serialized_data = form.serialize()