At the beginning of 1950, the large red M surrounded by a blue circle appeared, an example of which still exists at Sentier station. To make station entrances more visible, the sign bears a red-letter M, set in a blue circle that lights up at night, as well as a band that reads "Métro" in white letters.
From the 1960s onwards, the "antenna signpost" was introduced to indicate new exits or to replace old lampposts. The "Métro" lettering, written in blue on a white background, surrounded by two circles representing a radio antenna, evoked the concept of a network for the very first time.
It was in the 1970s that the famous luminous "yellow M" made its appearance. It was more legible and used the colors of the metro ticket. It is sometimes used with a very simple stainless-steel frame of recent construction, or adapted to an older iron or stone frame.
With the opening of metro line 14 in 1998, a new signpost was designed: it is a totem pole in the shape of an urban tree with two cast iron branches. Each of the glass panels held up by the branches features the modern M encircled three-quarters of the way up, as well as the name of the station, the lines serving it and the RATP logo.