The new DIN Standard 18940 for load-bearing masonry has been in effect since 2023. It applies to buildings up to 13 meters (42 feet) tall and regulates the principles for the design, construction, and execution of load-bearing unfired clay masonry.
Find out more here (short answer) and here (technical details) DIN 18940 (in German)
UK Green Building Council: Unfired clay bricks, Unfired earth blocks
BRE Group: Unfired Clay Masonry