Document mixed-line-ending limitation for fix={crlf,lf} with git.diff --git a/README.md b/README.md
index b0ea69b..fd62ffa 100644
--- a/README.md
+++ b/README.md
@@ -76,6 +76,7 @@
- `--fix={auto,crlf,lf,no}`
- `auto` - Replaces automatically the most frequent line ending. This is the default argument.
- `crlf`, `lf` - Forces to replace line ending by respectively CRLF and LF.
+ - This option isn't compatible with git setup check-in LF check-out CRLF as git smudge this later than the hook is invoked.
- `no` - Checks if there is any mixed line ending without modifying any file.
- `name-tests-test` - Assert that files in tests/ end in `_test.py`.
- Use `args: ['--django']` to match `test*.py` instead.
