French Prime Minister Gabriel Attal on Wednesday warned train controllers against disrupting travel during school holidays as ticket inspectors geared up to strike this weekend.
"The French know that going on strike is a right," Attal said, while adding pointedly that "working is a duty".
Every time rail workers strike during holidays the image of the SNCF rail company "takes a hit", he said, lamenting what he said was becoming a "kind of habit".
Train controllers plan to strike on Friday, Saturday and Sunday.
Christophe Fanichet, SNCF's passengers division chief, said the action meant that one out of two trains would be cancelled between Friday and Sunday.
"Not all trains are going to leave," Fanichet told broadcaster Franceinfo.
He encouraged travellers to postpone their travel until Monday or Tuesday, adding that the rail company planned "exceptional compensation" for those hit by the action.
Fanichet condemned the strike as "incomprehensible".
The action was announced after a Christmas strike in December, 2022 affected some 200,000 holidaymakers.
The unions say the company has been slow to fulfil the terms of the agreement negotiated at the end of 2022, but Fanichet disputed that.
"We promised additional jobs, and those jobs are there," he said.
SNCF head Jean-Pierre Farandou has said the company has promised to pay bonuses and is also raising wages.
"I don't see why we should have to respond by disrupting the lives of French people who want to go on holiday," he has said.