The use of double names, such as Reuilly - Diderot or Strasbourg — Saint-Denis, often goes back to two (or more) stations on separate lines that were originally named independently and became associated as interchange stations. For example, the station Marcadet - Poissonniers is an interchange station consisting of the original Marcadet on Line 4 and the original Poissonniers on Line 12. In many instances, however, the practice of double naming was extended to other stations, usually because these stations are located at the intersection of streets carrying these names.