Châtelet is connected by another long underground corridor to the southern end of the RER station Châtelet – Les Halles, the northern end of which is again connected to the Métro station Les Halles. The distance from Line 7 at Châtelet to the RER lines at Châtelet – Les Halles is approximately 750 metres (2,460 ft). It is the ninth-busiest station on the Metro system.
The station was opened on 6 August 1900, three weeks after trains began running on the original section of line 1 between Porte de Vincennes and Porte Maillot on 19 July 1900. The line 4 platforms were opened on 21 April 1908 as part of the original section of the line from Porte de Clignancourt to Châtelet. It was the southern terminus of line 4 until the opening of the connecting section of the line under the Seine to Raspail on 9 January 1910.
The line 7 platforms were opened on 16 April 1926 as part of the line's extension from Palais Royal to Pont Marie with the name Pont Notre-Dame-Pont au Change. It had no direct connection with Châtelet. On 15 April 1934 a connecting corridor was opened to the platforms of lines 1 and 4 and the line 7 station was renamed. The line 11 platforms were opened near the line 7 platforms on 28 April 1935 as part of the original section of the line from Châtelet to Porte des Lilas.