diff --git a/.git-blame-ignore-revs b/.git-blame-ignore-revs
new file mode 100644
index 0000000..42ced8b
--- /dev/null
+++ b/.git-blame-ignore-revs
@@ -0,0 +1,2 @@
+# trivial: apply black
+917a485d7b777b96ef8bd2d9aea2e55ea9b0fc92
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
new file mode 100644
index 0000000..a14705c
--- /dev/null
+++ b/.pre-commit-config.yaml
@@ -0,0 +1,8 @@
+# See https://pre-commit.com for more information
+# See https://pre-commit.com/hooks.html for more hooks
+repos:
+-   repo: https://github.com/psf/black
+    rev: 20.8b1
+    hooks:
+    - id: black
+      args: ['--target-version', 'py37', '--skip-string-normalization', '--line-length', '110']
diff --git a/README b/README
new file mode 100644
index 0000000..cb0d9a8
--- /dev/null
+++ b/README
@@ -0,0 +1,28 @@
+Passerelle plugin for 3M encombrants
+====================================
+
+Code Style
+----------
+
+black is used to format the code, using thoses parameters:
+
+    black --target-version py37 --skip-string-normalization --line-length 110
+
+There is .pre-commit-config.yaml to use pre-commit to automatically run black
+before commits. (execute `pre-commit install` to install the git hook.)
+
+License
+-------
+
+This program is free software: you can redistribute it and/or modify it under
+the terms of the GNU Affero General Public License as published by the Free
+Software Foundation, either version 3 of the License, or (at your option) any
+later version.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
+details.
+
+You should have received a copy of the GNU Affero General Public License along
+with this program.  If not, see <http://www.gnu.org/licenses/>.