How can I change a QWERTY keyboard layout to AZERTY without changing the phone language?
SwiftKey X supports the feature you are asking (English with AZERTY keyboard).  Try out their demo.

After you have installed the app, go to the Settings of SwiftKey.  Go to "Languages &amp; layouts"

Next to Englush, tap on the little keyboard icon.  Then choose AZERTY.

You'll now have English autocorrect on an AZERTY keyboard.