diff --git a/addons/mail/models/mail_message.py b/addons/mail/models/mail_message.py
index e7b40727029..306137fa723 100644
--- a/addons/mail/models/mail_message.py
+++ b/addons/mail/models/mail_message.py
@@ -908,7 +908,7 @@ class Message(models.Model):
                 ('res_id', '=', self.res_id)
             ]).filtered(lambda fol: self.subtype_id in fol.subtype_ids)
             if self_sudo.subtype_id.internal:
-                followers = followers.filtered(lambda fol: fol.partner_id.user_ids and group_user in fol.partner_id.user_ids[0].mapped('groups_id'))
+                followers = followers.filtered(lambda fol: fol.channel_id or (fol.partner_id.user_ids and group_user in fol.partner_id.user_ids[0].mapped('groups_id')))
             channels = self_sudo.channel_ids | followers.mapped('channel_id')
             partners = self_sudo.partner_ids | followers.mapped('partner_id')
         else:
diff --git a/addons/mail/static/src/js/chatter.js b/addons/mail/static/src/js/chatter.js
index ddd1aa5f5e0..15e51c253e2 100644
--- a/addons/mail/static/src/js/chatter.js
+++ b/addons/mail/static/src/js/chatter.js
@@ -114,7 +114,7 @@ var Followers = form_common.AbstractField.extend({
         var follower_id = $currentTarget.data('oe-id');
         var is_channel = $currentTarget.data('oe-model') === 'mail.channel';
         self.dialog = new Dialog(this, {
-                        size: 'small',
+                        size: 'medium',
                         title: _t('Edit Subscription of ') + $currentTarget.siblings('a').text(),
                         buttons: [
                                 {
@@ -131,7 +131,7 @@ var Followers = form_common.AbstractField.extend({
                                 },
                             ],
                 }).open();
-        return self.fetch_subtypes($currentTarget.data('id'));
+        return self.fetch_subtypes($currentTarget.data('id'), $currentTarget.data('oe-model'));
     },
 
     on_invite_follower: function (channel_only) {
@@ -270,8 +270,10 @@ var Followers = form_common.AbstractField.extend({
 
     /** Fetch subtypes, only if current user is follower or if follower_id is given, i.e. if
      *  the current user is editing the subtypes of another follower
+     *  @param {int} [follower_id] the id of the follower
+     *  @param {string} [follower_model] 'res.partner' or 'mail.channel'
      */
-    fetch_subtypes: function (follower_id) {
+    fetch_subtypes: function (follower_id, follower_model) {
         var self = this;
         var dialog = false;
 
@@ -292,7 +294,7 @@ var Followers = form_common.AbstractField.extend({
                 res_id: this.view.datarecord.id,
                 follower_id: follower_id,
             }).then(function (data) {
-                self.display_subtypes(data, dialog);
+                self.display_subtypes(data, dialog, (follower_model === 'mail.channel'));
             });
         } else  {
             return $.Deferred().resolve();
@@ -300,11 +302,11 @@ var Followers = form_common.AbstractField.extend({
     },
 
     /** Display subtypes: {'name': default, followed} */
-    display_subtypes:function (data, dialog) {
+    display_subtypes:function (data, dialog, display_warning) {
         var old_parent_model;
         var $list;
         if (dialog) {
-            $list = this.dialog.$el;
+            $list = $('<ul>').appendTo(this.dialog.$el);
         } else {
             $list = this.$('.o_subtypes_list ul');
         }
@@ -324,9 +326,14 @@ var Followers = form_common.AbstractField.extend({
             old_parent_model = record.parent_model;
             record.followed = record.followed || undefined;
             $(qweb.render('mail.Followers.subtype', {'record': record,
-                                                     'dialog': dialog}))
+                                                     'dialog': dialog,
+                                                     'display_warning': display_warning && record.internal}))
             .appendTo($list);
         });
+
+        if (display_warning) {
+            $(qweb.render('mail.Followers.subtypes.warning')).appendTo(this.dialog.$el);
+        }
     },
 
     do_follow: function () {
diff --git a/addons/mail/static/src/less/chatter.less b/addons/mail/static/src/less/chatter.less
index 35d5b3b7a76..839e419e88e 100644
--- a/addons/mail/static/src/less/chatter.less
+++ b/addons/mail/static/src/less/chatter.less
@@ -125,8 +125,11 @@
 }
 
 // Edit subtypes in dialog
-.modal .modal-body > li.o_subtype {
-    list-style: none;
+.modal .modal-body > ul {
+    padding-left: 0;
+    > li.o_subtype {
+        list-style: none;
+    }
 }
 
 @media print {
diff --git a/addons/mail/static/src/xml/chatter.xml b/addons/mail/static/src/xml/chatter.xml
index 6207cdb3980..cf6096bc8a9 100644
--- a/addons/mail/static/src/xml/chatter.xml
+++ b/addons/mail/static/src/xml/chatter.xml
@@ -154,7 +154,13 @@
             <span t-att-for="'input_mail_followers_subtype_'+record.id+(dialog ? '_in_dialog': '')">
                 <t t-esc="record.name"/>
             </span>
+            <i t-if="display_warning" class="fa fa-warning text-warning"/>
         </li>
     </t>
+    <t t-name="mail.Followers.subtypes.warning">
+        <span class="text-warning">
+            <i class="fa fa-warning"/> Be careful with channels following internal notifications
+        </span>
+    </t>
 
 </templates>