diff --git a/tox.ini b/tox.ini
index f9414425..3e15e1a9 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py3-django111-pg-coverage-pylint, py3-django22-pg
+envlist = py3-django111-pg-black-coverage-pylint, py3-django22-pg
 toxworkdir = {env:TMPDIR:/tmp}/tox-{env:USER}/chrono/{env:BRANCH_NAME:}
 
 [testenv]
@@ -32,8 +32,10 @@ deps =
   django22: django>=2.2,<2.3
   django111: djangorestframework<3.12.0
   psycopg2-binary
+  pre-commit
 commands =
   ./getlasso3.sh
   python3 setup.py compile_translations
   py.test {env:COVERAGE:} {posargs:tests/}
   pylint: ./pylint.sh chrono/
+  black: pre-commit run black --all-files --show-diff-on-failure