diff --git a/pyproject.toml b/pyproject.toml
index 69b8f4d..b193163 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,11 +1,12 @@
 [tool.black]
 target-version = ['py37']
+exclude = '^/swh/loader/cvs/(rcsparse|cvs2gitdump)/.*'
 
 [tool.isort]
 multi_line_output = 3
 include_trailing_comma = true
 force_grid_wrap = 0
 use_parentheses = true
 ensure_newline_before_comments = true
 line_length = 88
 force_sort_within_sections = true