I have changed my locale, keyboard and region to France and French keyboard, but the client didn't change its interface language to the desired language. I have tried all ways to enable the French language, but it appears it doesn't work. The client might not support French language or at least I didn't find a way to enable this language support.
Use the following link to open a support ticket where you can ask the developers about the possibility of changing the interface language: http://support.informer.com/?start&win