EchoSync has both English or French interfaces, but its site is in French; here's my translation of the relevant blurb...
Download EchoSync current version (click 'Telecharger') at http://www.luminescence-software.org/echosync/.http://www.luminescence-software.org/echosync/ wrote:Echosync: an application for file safekeeping, capable of diferential data backup. This program has been created to achieve four goals: speed, simplicity, flexibility and relliability.