Paris -- French rail workers and Air France staff are taking part in massive strikes across the country today, which the French press has dubbed "Black Tuesday."

The strikes pose a serious challenge to President Emmanuel Macron, who was elected into office eleven months ago.

Nearly 4.5 million train passengers are facing major disruptions from the strikes. Around half of the staff at state rail operator SNCF are on strike today, the company said in a statement, and workers have walkouts planned until June 28.

According to SNCF, only one of eight high-speed TGV trains is running and just one regional train is operating. Around the Paris area, less than half of RER region train services are in service. The walkout is also disrupting train traffic on the Eurostar, with three out of four trains running to London.

Railway unions are opposing Macron’s plan to reform the state rail operator SNCF, which could strip new hires of special advantages such as guaranteed jobs for life and early retirement. The French government argues its plan would make SNCF more competitive, but unions fear the changes are a first step toward privatizing the state rail operator.

These mass rail strikes are perceived as a first major test for the 40-year-old Macron; previous presidents have tried and failed to reform the state rail operator. Transport Minister Elisabeth Borne said this morning on French TV that the reform will pass, but insisted that the government is willing “to listen, to hold a consultation, to have a dialogue.” She said she is expecting to meet with rail unions on Thursday.

Air transportation was also disrupted in France today, as Air France personnel are on strikes for the fourth time in less than two months. The company said in a statement it expects to operate 75 percent of its flights, but added that last-minutes delays and cancellations may occur.

The Air France walkouts have no link to Macron’s reforms. Staff unions are demanding a 6 percent salary increase, arguing that airline management should distribute the wealth with its staff following strong financial results in 2017.

Three additional strikes are expected at Air France on April 7, 10 and 11.