diff --git a/README.md b/README.md
index 92d2cc9..809a788 100644
--- a/README.md
+++ b/README.md
@@ -131,7 +131,8 @@ In case of several configuration files, just set the configuration directory (wi
 1 0,12 * * * root /srv/statoolinfos/bin/statoolinfos probe -previousday /srv/statoolinfos/conf/ >> /srv/statoolinfos/cron.log
 ```
 
-Warning: in previous day mode, the metrics generated are overwrited for the last month, the last week and the last day. So, six weeks in logs are required.
+Warning: in previous day mode, the metrics generated are overwrited for the last month, the last week and the last day. So, **six weeks in logs are required**.
+
 
 ### Etherpad metrics