In May 2017 the new § 13b was amended to the German Federal Building Code (“BauGB“). § 13b BauGB introduces an alternate planning process to draft small-scale land development plans at the fringe of existing settlements, by referring to the procedural simplifications of § 13a BauGB. If the conditions of application of § 13b BauGB are fulfilled, planning processes are exempted from several procedural steps, such as the environmental impact assessment or environmental report. Planning processes, making use of the simplifications of § 13a BauGB, but missing the conditions of application from § 13b BauGB, result in plans, that are usually unlawful and void. Therefore, municipalities are highly affected by application problems of the new regulation. The article addresses the current and most important application questions of § 13b BauGB. On the one hand it analyses the material scope of application, which is connected to the legal term of “Wohnnutzung”. On the other hand it examines the geographical scope of application and the spatial relation to the planning process pursuant to § 13a BauGB. In consideration of jurisdiction and the scientific debate, the article proposes suggestions to provide greater legal certainty for local planning authorities.