Today in Postal History

This censored airmail cover was sent from Sao Paulo.
There is a single CDS.
There is also a hardly visible CDS with an 18 JUN 1942 date on the reverse.
I'm not sure what occasioned this mark.

The sender requested transport via Africa, Lisbon, and London.
This was confirmed by a boxed handstamp VIA AFRICA-LISBOA-LONDRES.
The sender appears to have been a government Commission of Imports and Exports.

At the time, Europe was consumed by World War II.
I don't think that the mail went through London.
I think it was diverted in Lisbon where Germany had
supporters and was sent via Germany where it was censored.
The Germans were interested in intercepting espionage
more than preventing casual transmission of sensitive facts.

The destination was Stockholm.
There are no receivers or other transit marks.
There is, however, a purple straightline date across the stamp for 28 JUL 1942.
I believe this was a receiving mark applied by the recipient.

There is also a script 823 on the front.
This was probably something applied while counting a stack of mail or?

The cover is franked with a single 1942 5000r blue Marshal Peixoto (Scott 525).