Verhaal

Children of James Catz and Louise née Van Dantzig

James Catz and his spouse Louise born Van Dantzig fled from Rotterdam with their two children Hans born April 1st, 1917 and Theo born March 5, 1921 to reach neutral Switzerland. They were arrested not too far from the border and conducted first to Besançon, Jura then transported to Drancy where the four were deported on November 4, 1942 by the convoy 40 to Auschwitz-Birkenau. The two young men escaped from the train and survived the war. Their parents perished and never returned. Hans published a book in english  The eye of the needle 

Sources : 

Serge Klarsfeld Memorial
https://stevemorse.org/france/sef.php?SurnameKind=exact&SurnameSoundex=&SurnameMax=CATZ&ConvoyKind=exact&ConvoyMax=40

French Journal Officiel (the children are listed as victims though)
https://www.legifrance.gouv.fr/download/pdf?id=qr2dQ-WEaRRx_8LYsjDpNL3ysyaKOB3hEJO7txQMLW4=

Book
https://books.google.co.il/books?id=Qp7QygAACAAJ

Memorial de la Shoah 
https://ressources.memorialdelashoah.org/notice.php?q=identifiant_origine:(FRMEMSH040870781970)

Deportation list
https://ressources.memorialdelashoah.org/zoom.php?code=216746&q=id:p_198319&marginMin=0&marginMax=0&curPage=0