diff --git a/Riot/Modules/MatrixKit/Views/MXKMessageTextView.m b/Riot/Modules/MatrixKit/Views/MXKMessageTextView.m
index 6cf574da0..fdbc037d3 100644
--- a/Riot/Modules/MatrixKit/Views/MXKMessageTextView.m
+++ b/Riot/Modules/MatrixKit/Views/MXKMessageTextView.m
@@ -119,8 +119,11 @@ - (NSAttributedString *)respectPreferredFontForAttributedString:(NSAttributedStr
                            inRange:NSMakeRange(0, workString.length)
                            options:0
                         usingBlock:^(id  _Nullable value, NSRange range, BOOL * _Nonnull stop) {
-        [workString removeAttribute:NSFontAttributeName range:range];
-        [workString addAttribute:NSFontAttributeName value:[(UIFont *)value fontWithSize:preferredFont.pointSize] range:range];
+        if ([value isKindOfClass:UIFont.class])
+        {
+            [workString removeAttribute:NSFontAttributeName range:range];
+            [workString addAttribute:NSFontAttributeName value:[(UIFont *)value fontWithSize:preferredFont.pointSize] range:range];
+        }
     }];
     [workString endEditing];
     
diff --git a/changelog.d/929.bugfix b/changelog.d/929.bugfix
new file mode 100644
index 000000000..b9d142d2e
--- /dev/null
+++ b/changelog.d/929.bugfix
@@ -0,0 +1 @@
+Depuis la gestion dynamique de taille d'affichage dans les salons, l'application plante quand le salon contient un message supprimé.
\ No newline at end of file