Many states in West Germany had standalone reparations offices. (It might be all of them did but I don't remember off the top of my head.) Those are the records you want to start with.
Do you have any family papers about restitution? That might give you an idea of which office handled their claim. For German Jews I assume that the office for the state that they were from would have handled the case, but I don't know for sure. As someone already mentioned the Berlin office covered eastern areas (East Germany and the parts of Germany that were given to Poland.)
If you have done an ITS/Arolsen Archives search for the people in question, and there are records, the central names index card or the T/D (case) file may indicate the relevant office. For example anything marked BLEA was a case handled by the Bavarian state office.
USHMM has United Restitution Records for Toronto (partial), Los Angeles and Buenos Aires. If it's possible that the claimant would have gone through one of those offices send me an email and I can check the indices. The rest of the records for Canada are at the Canadian Jewish Archives.
Finally I do not know if the Leo Baeck Institute would have relevant materials but it cannot hurt to check their archives catalog.
Megan Lewis, reference librarian
United States Holocaust Memorial Museum