diff --git a/module3/exo1/influenza-like-illness-analysis.ipynb b/module3/exo1/influenza-like-illness-analysis.ipynb
index 42523bf87ba659d959b9e71e2404f8863e2b582c..8d66766fd2b39d43825b525f7016618dfa3d2094 100644
--- a/module3/exo1/influenza-like-illness-analysis.ipynb
+++ b/module3/exo1/influenza-like-illness-analysis.ipynb
@@ -9,7 +9,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 17,
+   "execution_count": 41,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -28,11 +28,32 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 21,
+   "execution_count": 42,
    "metadata": {},
    "outputs": [],
    "source": [
-    "data_url = 'incidence-PAY-3.csv'"
+    "data_url = \"http://www.sentiweb.fr/datasets/incidence-PAY-3.csv\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "In order to protect us in case the Réseau Sentinelles Web server disappears or is modified, we make a local copy of this dataset that we store together with our analysis. It is unnecessary and even risky to download the data at each execution, because in case of a malfunction we might be replacing our file by a corrupted version. Therefore we download the data only if no local copy exists."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 43,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "data_file = \"incidence-PAY-3.csv\"\n",
+    "\n",
+    "import os\n",
+    "import urllib.request\n",
+    "if not os.path.exists(data_file):\n",
+    "    urllib.request.urlretrieve(data_url, data_file)"
    ]
   },
   {
@@ -59,7 +80,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 22,
+   "execution_count": 44,
    "metadata": {},
    "outputs": [
     {
@@ -1024,7 +1045,7 @@
        "[1882 rows x 10 columns]"
       ]
      },
-     "execution_count": 22,
+     "execution_count": 44,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -1043,7 +1064,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 23,
+   "execution_count": 45,
    "metadata": {},
    "outputs": [
     {
@@ -1105,7 +1126,7 @@
        "1645        FR   France  "
       ]
      },
-     "execution_count": 23,
+     "execution_count": 45,
      "metadata": {},
      "output_type": "execute_result"
     }