diff --git a/module3/exo1/analyse-syndrome-grippal.Rmd b/module3/exo1/analyse-syndrome-grippal.Rmd
index a946fee6240f2274931d7d5d81a53233a32c41ed..9190483f39f92194a7508daaa43e54c8e1c5b3e9 100644
--- a/module3/exo1/analyse-syndrome-grippal.Rmd
+++ b/module3/exo1/analyse-syndrome-grippal.Rmd
@@ -27,6 +27,7 @@ data_url = "http://www.sentiweb.fr/datasets/incidence-PAY-3.csv"
 
 data_file = "Incidence_grippe.csv"
 
+# We will download the dataset only if a local copy does not exist yet
 if (!file.exists(data_file)) {
     download.file(data_url, data_file, method="auto")
 }