Syria chemical attack false flag Idlib
It's based on circular logic. If anything, what little has been supposedly established actually points in the other direction
For over a week now France has claimed it has irrefutable evidence that Syrian military used gas against civilians earlier this month and would present it shortly.

It has now done so. It says it has determined that sarin used in the 2017 Khan Sheikhoun attack came from the same stock used in an earlier 2013 attack.

This is it. This is the extent of its super-duper evidence.

Because Paris "knows" the Syrian army used sarin in 2013, which Syria denies and was never proven, France now "knows" Syria also used sarin in 2017.

Anywhere else that would be called circular logic.

If anything, if samples from Khan Sheikhoun match sarin used in 2013 that makes it all the more likely that it came from rebel stock. The same stock they ultimately used to stage the East Ghouta false flag.