Châtelet–Les Halles station (French:[ʃɑtlɛleal]) is a major train hub inParis and the largest underground station in the world. Opened in 1977, it is the central transit hub for theParis metropolitan area, connecting three of fiveRER commuter-rail lines and five of sixteenMétro lines.[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 nearbyPlace du Châtelet public square andLes Halles, the former wholesale food market of Paris, now ashopping mall.

Formally, the name Châtelet–Les Halles designates theRER station alone. Informally, it refers to the hub comprising the eponymous RER station (served byRER A,RER B andRER D) plus the contiguousParis Métro stationsChâtelet (served byLine 1,Line 4,Line 7,Line 11 andLine 14) andLes Halles (served byLine 4).
For purposes ofwayfinding, the massive three station complex is broken up into three sectors: Forum, Rivoli and Seine.[5]
The Forum sector is named after the adjoiningForum des Halles shopping mall, which is accessible from this part of the station. The sector includes the RER platforms and theLes Halles station onParis Métro Line 4. The exits located in the sector are numbered 1 through 9.
The Rivoli sector is below and named after theRue de Rivoli, a major road known for its shopping and includes theChâtelet station ofLine 1,Line 4 andLine 14 of the Paris Métro. The exits located in the sector are numbered 10 through 14.
The Seine sector is named after the nearbySeine River and includes the Châtelet station ofLine 7 andLine 11 of the Paris Métro. The exits located in the sector are numbered 15 through 19.
The tracks of all three RER lines are oriented parallel along an east–west direction. The seven tracks are grouped on four platforms, with the outer platforms reserved for RER A and RER B and the central ones for RER D. This enables easy cross-platform connections between RER A and RER B trains traveling in the same direction, and a solution for those RER D trains which use the station as a terminus.
| G | Street Level | Entrance/Exit |
| B1 | Mezzanine | to Entrances/Exits, connections toChâtelet |
| Platforms (B2) | Track 1A | |
| Island platform, doors will open on the left, right | ||
| Track 1B | ||
| Track 3 | ||
| Island platform, doors will open on the left, right | ||
| Track Z | ||
| Island platform, doors will open on the left, right | ||
| Track 4 | ← | |
| Track 2B | ← | |
| Island platform, doors will open on the left, right | ||
| Track 2A | ← | |
A major renovation of the station complex and adjoiningForum 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.[6] The renovation included the construction of a major new entrance at Place Marguerite de Navarre, with direct access to the RER station hall; the complete renovation and enlargement of the RER station hall; and extension of key escalators to lower levels of the station.