diff --git a/tools/rapport_activite.sh b/tools/rapport_activite.sh
index 6887f08a..62d8d646 100755
--- a/tools/rapport_activite.sh
+++ b/tools/rapport_activite.sh
@@ -105,6 +105,7 @@ elif [ "$#" = 1 ] && [ "$1" = "-p" ]; then
     else [ "$(date +%m)" -eq 1 ]
 	 precedingMonth=12
 	 year="$(($(date +%Y)-1))"
+	 yearMonth="$year-$precedingMonth"
     fi
     monthEnglish=$(LANG=en_EN.UTF-8;date -d $year-$precedingMonth-01 +%b)
     echo -e "Rapport d'activité du service paste.chapril.org du mois $monthEnglish $year"