French faults were corrected by one of the members of the site www.frxoops.org (pseudo svm). There are also other modifications dedicated to French (name of the short months, public holidays).

Link to the thread on the frxoops :pical version francaise
Link to the path and author : piCal 0.86 Traduction FR

A lot of members of frxoops put this patch¡Ä and I recently use it in my modification of pical.