[3] The hub hosts 750,000 travellers per weekday (493,000 for the RER alone) and platforms separated by up to 800 metres (0.5 mi).

[4] It is named after the nearby Place du Châtelet public square and Les Halles, the former wholesale food market of Paris, now a shopping mall.

For purposes of wayfinding, the massive three station complex is broken up into three sectors: Forum, Rivoli and Seine.

The sector includes the RER platforms and the Les Halles station on Paris Métro Line 4.

A major renovation of the station complex and adjoining Forum des Halles shopping mall was completed in 2018, with the main aim of improving safety in the event of an emergency evacuation at peak traffic time.