Variable resourceBase contains incorrect path in multi-language websites

When my visitors browse my website using the default language English, resourceBase = "/sites/all/modules/civicrm/" which is correct. However, when they switch to the French language in my website, resourceBase = "/fr/sites/all/modules/civicrm/" which does not exist. So, they cannot see any images provided by civicrm because image links now refer to this directory "/fr/sites/all/modules/civicrm/". For example, my event pages display iCalendar images using non-existent file /fr/sites/all/modules/civicrm/i/office-calendar.png.