Unions representing workers for Paris transport body RATP announced that they will be showing solidarity with striking SNCF workers on Thursday March 22nd.
That means it could be a miserable day for commuters in and around Paris but also for train passengers across France.
The strike notice filed by seven out of nine unions called for a walk-out at 9pm on Wednesday March 21st until 8am on Friday March 23rd.
At the moment it is unclear how Metro and RER rail traffic will be impacted by the strike. Train and Metro have until 48 hours before the planned strike to declare whether or not they will walk out.
It all depends on how many workers answer the call of the various unions.
The motive for the strike is the government's plan to end the special employment status afforded to French rail workers, known as "cheminots", which gives them a so-called "job for life", automatic pay rises and early retirement.
Although rail workers with SNCF argue they deserve the benefits for the tough conditions they have to work in and the fact they have to work nights and weekends.
The controversial move was part of the French government's planned reforms of the rail network, which prompted the unions to declare all out war and threaten "historic" strikes.
Paris transport workers fear they could be next in line for government reforms so feel the need to support their colleagues at SNCF.
We will bring you information on he expected disruption to Metro and RER traffic as soon as we hear.