The jurisprudence of the Court of Cassation (1850-2015) is available on the Ministry of Justice website. Note that some years are missing. For the most recent period, jurisprudence, all jurisdictions combined, is available on Juridat. For World War II, see La jurisprudence belge depuis le 10 may 1940 byThéodore Smolders, Etienne De Fays, Freddy Genin and Yves Meulemans:

Volume Year of publication Digital copy
I 1941 Digithemis
II 1941 Digithemis
III 1942 Digithemis
IV 1943 Digithemis
V 1943 Digithemis
VI 1945 Digithemis