diff --git a/module2/exo4/exercice.ipynb b/module2/exo4/exercice.ipynb
index 0bbbe371b01e359e381e43239412d77bf53fb1fb..8bab3da68d21415dad52674f6381e1791958e81e 100644
--- a/module2/exo4/exercice.ipynb
+++ b/module2/exo4/exercice.ipynb
@@ -1,5 +1,26 @@
 {
- "cells": [],
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Extensions jupyter décrit dans https://stackoverflow.com/questions/49189154/numbered-headers-in-jupyter-notebooks ou http://jupyter-contrib-nbextensions.readthedocs.io/en/latest/\n",
+    "\n",
+    "* Table des matières\n",
+    "* Traduction d'une cellule, etc.\n",
+    "\n",
+    "\n",
+    "Pour installer : `pip install jupyter_contrib_nbextensions jupyter_nbextensions_configurator`"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
  "metadata": {
   "kernelspec": {
    "display_name": "Python 3",
@@ -16,10 +37,9 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.6.3"
+   "version": "3.6.4"
   }
  },
  "nbformat": 4,
  "nbformat_minor": 2
 }
-