Two out of three high-speed TGV and regional trains are to be cancelled during Monday's strike, the 18th of a rolling programme of industrial action that started at the beginning of April
There are likely to be even fewer trains on parts of the RER Paris regional network, including on the RER B line that links Charles de Gaulle airport to the city.
Two out of five international trains are to run, except for the Eurostar to London and the Thalys to Brussels and Amsterdam which are expected to run more or less as normal.
The company says it has been warned that demonstrations such as occupations of stations and blockades of rail lines will take place.
French transport workers are obliged by law to inform their employer 48 hours ahead of taking part in a strike.
They are also carrying out a vote on the reform this week.
A meeting with Prime Minister Edouard Philippe last week failed to resolve the dispute and two out of four unions refused to meet Transport Minister Elisabeth Borne on Friday.