From
http://www.easytravelreport.com/index.html
French general strike is planned for Tuesday, 12 September 2017
Air France Pilot Strike
Air France pilot strike is planned from 9th to 12th of September, 2017.
In line with the general strike.
Striking pilots belong to SPAF pilot union, which is considered a minor union compared to SNPL-ALPA which has 50% or more of Air France pilots enrolled with. Momentum may encourage other Air France unions to join in.
Air France management can easily cover this strike action. Trouble comes as these dates will coincide with a French general strike. If the pilot's don't get you other aviation unions workers will.