MBA 2015 Keycaps problems

[UbiCrea]

Hi,
I've a MacBook Air 2015 for my son and I bought it abroad for cheap. I just need to replace the keycaps to switch the keyboard in French.
I bought on Aliexpress a bundle of French keycaps compatible with MPA 2015 and MBP 2015.
But when I tried to replace the keycap, they are not the same.
So I looked again and everywhere I see keycaps compatible with all of the MBP Retina > 2015 and MPA > 2017...
On the left is the original and on the right the new one from AE.
Does anyone know how come my keyboard is "special" ?

On the left is the original, on the right the new one from AE vv

Here is the Scissor from my keyboard vv

And here is the new keycap nearby vv

And the original keycap nearby vv

Thanks a lot