u/Minatoku92

In April 2026, the replacement of switches on Line 4 required the closure of the line between Châtelet and Barbès–Rochechouart. The southern terminus of the northern section of Line 4 was Barbès–Rochechouart, where the reversing switch is located just north of the station.

This explains how two trains can arrive at the same time on stations: one arrives from the north to let passengers disembark, while the second returns to the boarding platform to pick up passengers before heading north again. For better passenger flows, the operator chosed to use separate platforms for boarding and disembarking.