What is the fine-grained topic of the following text: Leading Slovenian politicians, policymakers and educators as well as embassy and business representatives attended the opening of the building which is the first in the country to be certified to strict German DGNB standards for building sustainability and one of the first pilot projects to contribute research to the European Commission’s Level(s) initiative. Only return the topic.
Opening of the first building in Slovenia certified to German DGNB sustainability standards