If you want to see all backend labels in French, you should translate them from Administration >> Interface Labels & Messages
. Currently the translations are only in English and we will have several language packs shortly.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items