diff --git a/WikiENS/settings.py b/WikiENS/settings.py
index 9c9fa74..25a083a 100644
--- a/WikiENS/settings.py
+++ b/WikiENS/settings.py
@@ -161,6 +161,9 @@ AUTHENTICATION_BACKENDS = [
     'allauth.account.auth_backends.AuthenticationBackend',
 ]
 
+ACCOUNT_ADAPTER = 'shared.allauth_adapter.AccountAdapter'
+SOCIALACCOUNT_ADAPTER = 'shared.allauth_adapter.SocialAccountAdapter'
+
 HOME_URL = reverse_lazy('wiki:root')
 
 LOGIN_URL = '_profil/login/'
diff --git a/shared/allauth_adapter.py b/shared/allauth_adapter.py
new file mode 100644
index 0000000..d8c8847
--- /dev/null
+++ b/shared/allauth_adapter.py
@@ -0,0 +1,20 @@
+from allauth.account.adapter import DefaultAccountAdapter
+from allauth.socialaccount.adapter import DefaultSocialAccountAdapter
+
+
+class AccountAdapter(DefaultAccountAdapter):
+    def is_open_for_signup(self, request):
+        return False
+
+
+class SocialAccountAdapter(DefaultSocialAccountAdapter):
+    def is_open_for_signup(self, request, sociallogin):
+        # sociallogin.account is a SocialAccount instance.
+        # See https://github.com/pennersr/django-allauth/blob/master/allauth/socialaccount/models.py
+
+        if sociallogin.account.provider == 'clipper':
+            return True
+
+        # It returns AccountAdapter.is_open_for_signup().
+        # See https://github.com/pennersr/django-allauth/blob/master/allauth/socialaccount/adapter.py
+        return super().is_open_for_signup(request, sociallogin)