French Air Traffic Controllers began striking on Monday over working conditions and current hours. The strike, scheduled to last until Friday, is expected to cause over 1,000 delays and cancellations. The strike also affects any flights travelling through French airspace, so flights have been rerouted as a result. ATC strikes reached an all-time high in 2016, with 41 days disrupted. Ryanair has complained to the the French Government about the high strike numbers. Transport Minister Alain Vidales released a statement condemning what he calls the "largely incomprehensible" strikes that have cost over $9 billion over the course of the last five years.
See "A Thousand Flights to be Cancelled As Week-Long Air Traffic Control Strike Starts in France", Cecilia Rodriguez, Forbes, March 7, 2017