FAQ: what to do in case of an alert

FAQ: what to do in case of an alert

Frequently Asked Questions about the La Défense Security Plan

01 - What is the La Défense Security Plan (PMSD)?

The La Défense Security Plan or "PMSD" is a system designed to facilitate the intervention of emergency services in the event of a major event on the La Défense site (terrorist attack, aircraft crash, etc.).

This plan, designed by the State services, in collaboration with Paris La Défense and the municipalities of Puteaux, Courbevoie, Nanterre and Neuilly-sur-Seine, plans and organises the alert procedure and the management of flows for better management of the event.

02 - What should I do if I witness a serious incident at La Défense?

First of all, take cover (confine yourself if you are in a building; escape if you are outside). Then call the emergency services (17 police or 18 fire brigade).

If you are in a tower, do not evacuate without prior instructions from your security service.

03 - How will I be notified in the event of a major event at La Défense?

In the event of a major event at La Défense, you may be notified by :

  • Your organisation (Human Resources Department, Security or Safety Department, etc.);
  • Sound messages broadcast on the La Défense site;
  • Audio messages in the CNIT and Westfield Les 4 Temps shopping centres, and possibly in your tower.
  • Visual messages broadcast on RATP and SNCF billboards;
  • Visual messages on the billboards in Nanterre, Neuilly-sur-Seine, Courbevoie and Puteaux;
  • Messages broadcast on the Prefecture website as well as on the Facebook and Twitter account of the Prefect of Hauts-de-Seine.
  • An alert from the authorities via the SAIP application from the Ministry of the Interior (available on the App Store or Google play)

04 - How do I know where to evacuate?

The evacuation of the site corresponds to a simple logic. You must evacuate beyond the ring road.

The diagram below shows the preferred evacuation routes according to your location on the La Défense site: evacuation plan.

You must follow the dedicated signposting (green panels) to indicate the evacuation routes.

The national and municipal police will also be present to show you the way.

05 - What is sheltering?

It consists in staying in a closed place, under cover, until the order to leave is given. It is recommended to stay close to a source of information (radio, computer, TV...).

06 - What is the purpose of the security perimeter?

The security perimeter delimits the area in which the public is prohibited. It is a zone secured by the police which facilitates the work of the emergency services and investigators.

The security perimeter can also delimit the zone inside which it is forbidden to enter without protection, under penalty of health risks (hypothesis of dispersion of chemical agents for example).

07 - After the evacuation, where can I find information about the incident in progress?

The public authorities (prefecture, local authorities, etc.) will communicate with the population and the press. Information about the incident will therefore be relayed on the main news channels (TV and radio) or on newspaper websites.

The Twitter account and the Facebook page of the Hauts-de-Seine Prefect will also allow for the delivery of ongoing messages.

Information points will be set up by town halls to provide information in the event of mobile phone network saturation.

08 - Is there a risk of saturation of the mobile phone network?

Given the number of users present simultaneously on the La Défense site, the risk of network saturation following a serious incident is very likely.

Therefore, in the event of an alert in the La Défense area, you are asked not to use your mobile phone in order to avoid any saturation phenomenon.

09 - In the event of an evacuation, do I have to pick up my vehicle parked in the basement of La Défense?

No. The traffic management plan associated with a major event provides for the closure of the ring road to public traffic for the benefit of emergency vehicles (ambulances, etc.).

In order not to hinder the free movement of emergency vehicles on the ring road, users are therefore asked not to collect their vehicles but to follow the evacuation instructions (evacuation on foot).

10 - If I see the employees of the tower opposite the one in which I work being evacuated, should I also evacuate automatically?

No !

The evacuation order will be given to you by the security service of your tower.

11 - What do the different sectors of La Défense correspond to?

They correspond to the signage developed by Paris La Défense.


To help you find your way around, consult the map of La Défense