I used GLFW on Windows 7 with an AZERTY keyboard, when I call "glfwGetKey('A')" everything works fine.
Next, I currently try to port my app to Mac, but when I call the same function "glfwGetKey('A')", I get a response only if I press "Q" key.
My Mac is also in AZERTY. I tried with other keys and same bug happened.
That is an unfortunate limitation of GLFW 2. It has been fixed in GLFW 3, but for 2 there's sadly no working around it.