On 30 January 2023, it was announced that the museum would close down in the autumn, with part of the collection being integrated into the Belgian Comic Strip Center.

[5] The museum's location was symbolic, since Marc Sleen started his career as cartoonist in 1947 whilst working for the newspaper De Nieuwe Gids, whose office was located on the Rue des Sables/Zandstraat.

[4][6] It exhibited original art work and memorabilia by Marc Sleen, as well as an overview of his long and versatile career, including his nature documentaries that he made for the Belgian TV show Allemaal Beestjes ("All kinds of animals").

One specific story, Het Spook uit de Zandstraat ("The Ghost of the Zandstraat") has been translated into English, French and German, and was made available as a souvenir for tourists.

[4] The museum organised a special tourists' route in Brussels, based on several locations that appeared in Nero comic book albums, including the Black Tower, Palace of Justice, Chapel Church, Sablon/Zavel, Central Station, Grand-Place/Grote Markt and Manneken Pis.