Joseph de Leeuwe was married to Helena Kan. The couple had two children: Klara and Emilie. Joseph de Leeuwe was insurance broker. Together with Emanuel Mozes de Leeuwe he ran an office in Rotterdam.
Addition of a visitor of the website.
In addition, a Jokos file (number 7868) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.The Jokos file reveals that a claim was lodged for compensation for valuables surrendered to the Lippmann-Rosenthal looting bank (L-claim, number 7171/16120).