Train drivers and other staff are set to walk off the job from tonight at the start of three months of planned stoppages against reform plans announced by President Emmanuel Macron and his government.
SNCF said only 15 percent of high-speed TGV trains would operate, along with one in five regional trains.
Only one in three trains between France and Germany and 75 percent of Eurostar trains between Paris and London will be operating.
Commuter services also will be reduced.
Four labour unions have called on rail workers to strike for two days every week until the end of June in reaction to government plans to revamp the debt-laden SNCF ahead of being opened to competition in 2019.
Despite consistent denials from the government, unions believe the reforms are the first step toward privatisation.
Under the proposed changes, new rail employees will not benefit from a special status historically given to railway workers, which guarantees them a job for life and early retirement.
France’s transport minister has described the strike action as “unjustified” and "incomprehensible”.
In an opinion poll conducted by Ifop for JDD and published on Sunday, 46 percent of the French said they thought the strike was justified, while 53 percent found it unjustified.
On Sunday Air France unions representing both flight crews and ground staff announced a new two-day strike for April 10 and 11, the latest move in its pay dispute with the French flag carrier since February.