Both parts of the lettering were renewed in 2018 and shine in an intense blue. As I learned during a conversation at the anniversary celebration “65 years City Universum Karlsruhe” on 09.10.2018, however, they are now no longer classic light tubes, but LED elements.
During the 2018 restoration, only part of the lettering was visible at a time.
The two-part neon sign is probably one of the oldest in Karlsruhe. It can already be seen on the building in a photo from December 1962: