diff --git a/CHANGES.rst b/CHANGES.rst
index ad91a9c07f..4cfae4024b 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -9,6 +9,7 @@ v9.9.9 (unreleased)
 - chore: bump actions/setup-python version (#1773, #1775)
 - refactor: switch to pyproject.toml (#1753)
 - chore: bump dependencies (#1774, #1777)
+- fix: IRC log message when leaving a room (#1782)
 
 
 v6.2.1 (2026-06-06)
diff --git a/errbot/backends/irc.py b/errbot/backends/irc.py
index d714f39aa2..f1ad41f7d7 100644
--- a/errbot/backends/irc.py
+++ b/errbot/backends/irc.py
@@ -552,7 +552,7 @@ def on_part(
         if self.bot.bot_identifier.nick == leaving_nick:
             with self._rooms_lock:
                 self.bot.callback_room_left(self._rooms[leaving_room])
-            log.info("Left room {}.", leaving_room)
+            log.info("Left room %s.", leaving_room)
 
     def on_endofnames(
         self, connection: irc.client.ServerConnection, event: irc.client.Event