3117 the emergency number
With 3117, SNCF Transilien can facilitate the intervention of emergency services.
Note that 3117 is a supplementary number: it does not replace the numbers for the relevant public emergency services in France: 18 for fire services, 17 for the police, 15 for a medical emergency, and 112 for an emergency in Europe.
3117 relays your call towards the relevant public authorities: fire services, police, emergency medical services, etc. When you dial 3117, emergency services can get real time localisation of the call to enable them to intervene more quickly.
When you dial 3117, you will be connected with a dedicated 3117 operator at the SNCF Transilien call centre. The operator will ask you for some key information that will be used to determine your location. Your phone number will be noted so that you can be called back if the call is disconnected. All calls are recorded.