No, the Paris Metro is not generally free for all children, but there are significant discounts based on age. As of 2026, children under the age of 4 travel for free on the entire RATP network (Metro, RER, Bus, and Tram), provided they do not occupy a separate seat if the train is crowded. For children aged 4 to 9 (inclusive), a 50% discount applies to single tickets and "carnets" (packs of 10 tickets). Once a child turns 10, they must pay the full adult fare for standard tickets. However, for residents or long-term visitors, the Imagine R student pass offers a heavily subsidized annual rate. For tourists, the "Paris Visite" pass also offers a child version at half the price of the adult pass for children aged 4 to 11. It is important to always carry proof of age (like a passport copy) when using a child-fare ticket, as RATP inspectors are strict and can issue immediate fines if a child appears older than their ticket allows.