Managed to find both the last contravention and the notice of reimbursement.
2nd of July 2016 on the RN 77 at Pontigny 89230
89 km/hr in a 70 zone
La vitesse retenue est de 84 km/hr…The retained speed is 84 km/hr, thus a ‘true’ speed 5 km/hr less than the ‘recorded’ speed.
So, if you are right Franglais and Pierrot, then the reduced ‘grace’ has been reduced since then.
I never assume that I can do 4 km/hr over, but if you are right, a decision to slam the anchors on for a hidden sign will have to be taken more often. 
The notice of reimbursement was sent on the 1st of January 2017 and it was specifically for no infractions since Pontigny. I have had none since, so I can only assume, as that notice said I now have 9, that previous infractions had less than 6 months between them and are thus still current.
I seem to remember reading somewhere that if you don’t have 6 months clear then points before that date have to last for 2 years. If that is true then I expect to be back up to 12 any time in the next couple of months. 
A bit of detail on what happened. I was travelling south after delivering a dog to Laubach in Germany and the 70 zone was a slow down for the 50 entering Pontigny. There is a routier just inside the boundary on the left and I was looking for that but my eyes were diverted left by the large Daf dealership opposite the camera. The camera wasn’t hidden but was at the end of a long line of trees which obviously added to my distraction. Easily done. 