Arduino Leonardo Keyboard writing wrong character "\"

Hi everybody,
I try to use my arduino leonardo as a keyboard to write some characters but i have some problems.
When i try to print a backslash with :

keyboard.print("\");

or

keyboard.write(92);

I have a 4 and not , sometimes i have a *
I'm using a french keyboard (azerty) and my windows system option for the keyboard is right. As well i modified the keyboard.cpp to use an azerty configuration.
I don't know why i have this problem, all characters work fine but not the
Do you have any idea to fix this ?
Thank you very much ! (and sorry for my english)