diff --git a/addons/web/static/src/js/views/calendar/calendar_renderer.js b/addons/web/static/src/js/views/calendar/calendar_renderer.js
index 9d9b09665c4..70dc4fb70d1 100644
--- a/addons/web/static/src/js/views/calendar/calendar_renderer.js
+++ b/addons/web/static/src/js/views/calendar/calendar_renderer.js
@@ -198,7 +198,6 @@ return AbstractRenderer.extend({
      */
     getAvatars: function (record, fieldName, imageField) {
         var field = this.state.fields[fieldName];
-        var value = this._format(record, fieldName);
 
         if (!record[fieldName]) {
             return [];
@@ -210,6 +209,7 @@ return AbstractRenderer.extend({
         } else if (field.type === 'many2one') {
             return ['<img src="/web/image/'+field.relation+'/'+record[fieldName][0]+'/'+imageField+'" />'];
         } else {
+            var value = this._format(record, fieldName);
             var color = this.getColor(value);
             if (isNaN(color)) {
                 return ['<span class="o_avatar_square" style="background-color:'+color+';"/>'];
diff --git a/addons/web/static/test/views/calendar_tests.js b/addons/web/static/test/views/calendar_tests.js
index fdd7892e42a..a73b456a49c 100644
--- a/addons/web/static/test/views/calendar_tests.js
+++ b/addons/web/static/test/views/calendar_tests.js
@@ -315,6 +315,34 @@ QUnit.module('Views', {
         calendar.destroy();
     });
 
+    QUnit.test('rendering, with many2many', function (assert) {
+        assert.expect(1);
+
+        this.data.event.fields.partner_ids.type = 'many2many';
+
+        var calendar = createView({
+            View: CalendarView,
+            model: 'event',
+            data: this.data,
+            arch:
+            '<calendar class="o_calendar_test" '+
+                'date_start="start" '+
+                'date_stop="stop" '+
+                'all_day="allday"> '+
+                    '<field name="partner_ids" avatar_field="image" write_model="filter_partner" write_field="partner_id"/>'+
+            '</calendar>',
+            archs: archs,
+            mockRPC: mock_check_access_rights,
+            viewOptions: {
+                initialDate: initialDate,
+            },
+        });
+
+        assert.strictEqual(calendar.$('.o_calendar_filter_items .o_cal_avatar').length, 3,
+            "should have 3 avatars in the side bar");
+
+        calendar.destroy();
+    });
 });
 
 });