Everything so far would point to sabotage as the obvious - but as we know that isn't always the case. However, it if were to be I doubt the Egyptian airspace is a direct corrolation to this as the only way such a system would work would be on a GPS reliant system. If it is sabotage, it's more likely based on a timer or an altitude as we've seen previously - was the aircraft beginning to descend?
It may have been timed to occur based on a calculation when it entered said airspace but not directly related to it entering said airspace, if that makes sense.
Regardless, it raises concerns about security at CDG if it was the case. Was the aircraft on the ground long at CDG? The time of this is also important - just as the West begins it's holiday "Season" which would have substantial consequences for Egypt's already severely damaged tourism industry.