The CGT-Cheminots union issued a strike notice for Thursday, December 16th and Friday, December 17th, in protest at what one rail worker at Gare du Nord described as ‘excess pressure on station positions: ticket agents, information points’.

“For Thursday, December 16, we recommend that travellers limit their trips as much as possible, with an average of 2 out of 3 trains running,” SNCF said in a statement.

RER traffic forecasts for Thursday are as follows: 

RER A: normal service;

RER B: Three out of four trains will operate;

[⚠️Mouvement social ] Les 16 et 17 décembre, mouvement social #RERB. Jeudi 16 prévoir 3 trains sur 4 toute la journée sur l’ensemble de la ligne. [1/2]

— RER B (@RERB) December 14, 2021

RER C: One train in three is expected to run;

RER D: 1 train out of 3 with bus between Corbeil-Malesherbes, Corbeil-Melun and Corbeil-Juvisy via Ris-Orangis. No RER D between Gare-de-Lyon and Châtelet-les-Halles. A replacement bus service has been set up between Corbeil-Essonnes and Juvisy via Ris-Orangis, between Corbeil Essonnes and Malesherbes and between Corbeil-Essonnes and Melun.

⚠ Mouvement social local – Jeudi 16 et vendredi 17/12⚠ :

Le trafic de la ligne sera fortement perturbé.

👉⏱RDV mercredi 17h pour vérifier vos horaires en consultant le calculateur d'itinéraire ou la rubrique « Fiches horaires » du site https://t.co/uRmNGCxxnx ⬇ pic.twitter.com/kECwDOo3JK

— RER D (@RERD_SNCF) December 13, 2021

RER E: One train in two will be cancelled.

For up-to-date information on RER services in the capital, click HERE

Meanwhile, Transilien rail services will be “highly disturbed” on line R, “very disturbed” on lines N and U, and “disturbed” on lines H and P, SNCF said. 

🔴 Mouvements Sociaux Locaux – 16 & 17 Déc. 2021
La circulation des trains pourra être perturbée sur certaines lignes. Nous vous invitons à anticiper vos déplacements, en vous rendant la veille, à 17h, sur l'un de ces médias 📲 https://t.co/arZJxFCmUz / https://t.co/mj23ybm3No pic.twitter.com/G5ADahWXRy

— SNCF Transilien (@Actu_Transilien) December 14, 2021

The travel forecast is as follows:

Line H:Two out of three trains will operate. A replacement bus service has been set up between Creil and Pontoise;

Lines J and L: normal service;

Line P: Four trains out of five will run on average;

Line R: One scheduled service in three will run on average. A replacement bus service has been set up between Melun and Montereau via Héricy;

Lines N and U: One train in two will be cancelled;

Tramway T11: Trams will run every 23 minutes;

T4: normal service.

For up-to-date information on Transilien services, click HERE

RATP networks except RER B, which it runs in partnership with SNCF, are unaffected.

Arnaud Bertrand, president of the association Plus de Trains which campaigns for improved rail services, called on travellers who can telecommute to do so. “We’ll need to leave room for employees who can’t do anything else but go to their workplace,” he told Le Parisien.

“This strike comes at a time when Île-de-France mobilités is still operating a reduced service due to the health crisis.”