diff --git a/src/lerobot/datasets/backward_compatibility.py b/src/lerobot/datasets/backward_compatibility.py
index a087c8ce7..0901bf255 100644
--- a/src/lerobot/datasets/backward_compatibility.py
+++ b/src/lerobot/datasets/backward_compatibility.py
@@ -71,7 +71,7 @@ class CompatibilityError(Exception): ...
 class BackwardCompatibilityError(CompatibilityError):
     def __init__(self, repo_id: str, version: packaging.version.Version):
         if version.major == 2 and version.minor == 1:
-                message = V30_MESSAGE.format(repo_id=repo_id, version=version)
+            message = V30_MESSAGE.format(repo_id=repo_id, version=version)
         else:
             raise NotImplementedError(
                 "Contact the maintainer on [Discord](https://discord.com/invite/s3KuuzsPFb)."