French to English keyboard swap possible?

Sorry to tell you Apple won’t swap out keyboards only the full uppercase and only with the same one not altering to a different keyboard unit.

So what I would do - Get a set of stickers as the gap to the screen is much less in this series than in years past. There are some keyboard skins which are ultra thin but they don’t lay down as well (like food wrap) Ultra Thin Keyboard Cover

You really want the other keys! Replacing the key caps is not easy and be ready needing to order a second or even a third wave of key caps! And you also have an ISO keyboard layout which has a few different keys like the Return and Shift keys than the US ANSI layout ANSI vs ISO: Explained & How to identify your Apple keyboard layout by country or region. This could end up quite expensive and is risky KeyCaps parts. As the M series is so new you might want to talk with the BookYard before ordering to make sure these will work.

The other option is just replace the full uppercase assembly as replacing the keyboard its self is just not possible in this series as its riveted and like I explained the physical keys are not laid out in the same configuration. This is by far the most expensive solution but in many ways is the easiest! Sadly it will be still awhile before these will be available.

The last option is just use an external keyboard, while not very practical for a laptop it is by far the safest option!