Here is the Bouygues FR 4.4 Kit Kat with Sense 5.5 RUU version 4.20.1020.12
It has radio version 4A.23.3263.28 and will work with this config:
File name is:
RUU M7 UL K44 SENSE55 MR Bouygues FR 4.20.1020.12 Radio 4A.23.3263.28 10.38r.1157.04L Release 351533 Signed 2
You should not need to downgrade your hboot version for this RUU to work. This should work for most S-On users that need to return to stock since there a lot are on a software/hardware versions lower than it.
If you need support for using this file you can use this XDA thread:
The full list of RUU files can be found here: