## 1 Introduction
### Public Procurement Practice in Germany  
Germany's public procurement takes place nationally, on the level of the Federal States (named 'Lander'), and in municipalities. Box 1 provides details. The country's public procurement is influenced by both European and national regulation. Box 2 provides an overview of important framework conditions. Germany's public procurement takes place on the federal and national level. Procurement in the individual Federal States is organized individually and differently by each state. There are central procurement offices, such as in the state of Rhineland-Palatinate, but there are also states in which public procurement is decentralized. The state administration of North Rhine-Westphalia offers an example of decentralized purchasing processes. In this state administration, purchasing is carried out by the individual departments (Ressors). The degree of centralization within the departments varies. In rare cases, products are procured jointly by several authorities of this Federal State. Most commonly, in the two example states, the procurement units act individually. This article's interview series considers this variety. (Source: own figure inspired by [34]). [style=MyFrame]  
**Box 2. ** Fundamental public procurement rules in Germany. [style=MyFrame]  
Germany's legal framework for public procurement is based on the European Directives 2014/23 EU, 2014/24/EU [35], which is particularly relevant in the given context and Directive 2014/25/EU. In 2016, Germany transposed the directives into German law. This resulted in an update of the Act against Restraints of Competition (Gesetz gegen Wetthewersbeschrankung, GWB), in the publication of the Procurement Ordinance (Vergabbeverdntung, VgV), and of two other regulations. Procedural rules are specified in the Subthreshold Procurement Ordinance (Unterschwellenvergabeordnung, UVgO), and in the Procurement and Contract Regulations for Construction Works Parts A and B (Vergabe- und Vertragsordnungen fur Bauleistungen Teil A und B, VOB/A and VOB/B) [36; 37]. The Federal States have further rules for public procurement. [style=MyFrame]  
Relevant procurement procedures according to the UVgO are (see [38; 39]):  
[style=MyFrame]  
\(\lx@sectionsign\) 9 Public invitation to tender  
[style=MyFrame]  
\(\lx@sectionsign\) 10 Restricted invitation to tender with competition (up to an anticipated contract value of EUR 100,000)  
[style=MyFrame]  
\(\lx@sectionsign\) 11 Restricted invitation to tender without competition  
[style=MyFrame]  
\(\lx@sectionsign\) 12 Negotiated award with or without a call for competition (up to EUR 10,000 without competitive bidding)  
[style=MyFrame]  
\(\lx@sectionsign\) 14 Direct contract (up to an anticipated contract value of EUR 1000). Box 2 refers to fundamental European and national framework conditions. When the EU directives were transposed into German law, the environmental aspects were also anchored. In 2015, the European Commission adopted the first EU CE Action Plan and in 2019 the Commission adopted the final Circular Economy Package. Germany's Kreislaufwirtschaftgesetz KrWG was published in 2012 and updated several times after 2019. The Federal Climate Change Act (September 2019) [40] and the Section 45 of the KrWG have also added the requirement to take account of climate protection and regulations to focus on purchasing resource-saving products. Internationally, the UN SDG No. 12 includes the target 12.7 (also called SDG 12.7) \"Promote sustainable public procurement practices in accordance with national policies and priorities.\" In the European context, the new EU CE Action Plan (March 2020) also takes into account developments towards more environmentally friendly public procurement [41]. However, the public procurers have different possibilities to (voluntarily) consider environmentally friendly aspects during purchasing. For example, it can be reflected whether a new product is required or if a used or rented product is more favourable.