The IWPA was re-opened two weeks after the beginning of the Second World War as the Central Agency for Prisoners of War, now based on the mandate from the 1929 Geneva Convention.
Once again, Étienne Clouzot played a prominent role: 
"in 1939, fuelled by his experience in the International Prisoners of War Agency, he helped organize the Central Prisoners of War Agency, becoming a member of its Technical Directorate"
Another key person became Suzanne Ferrière, who had assisted her uncle Frédéric at the IPWA during WWI and now instituted a new family messaging system.

Already in October 1939, IBM "provided the Agency free of charge with both staff and Watson machines.
The latter, thanks to a perforated card system, made it possible to sort and classify information at high speed."
Faced with a gigantic growth of personal and institutional data which was handled by some 3,000 staff, the ICRC in 1942 introduced its first filing system.
Altogether, the number of index cards rose to about 45 million and the number of transmitted messages to some 120 million, reflecting the new dimensions of human suffering.
The ICRC's efforts were awarded in 1944 with its second Nobel Peace Prize after 1917.


One of the last - and most important - documents from the WWII period was issued on 29 August 1945, only days before the end of the war, by Fritz Bilfinger, an ICRC delegate who reached the apocalyptic ruins of Hiroshima just some three weeks after the United States Army Air Forces (USAAF) dropped the atomic bomb "Little Boy" on the Japanese city.
His telegram, kept in the archives, recorded a chilling warning of the horrors of the Atomic Age:
“conditions appalling stop city wiped out, eighty percent all hospitals destroyed or seriously damaged; inspected two emergency hospitals, conditions beyond description full stop effect of bomb mysteriously serious stop many victims, apparently recovering, suddenly suffer fatal relapse due to decomposition of white blood cells and other internal injuries, now dying in great numbers stop estimated still over one hundred thousand wounded in emergency hospitals located surroundings, sadly lacking bandaging materials, medicines stop.”
The IWPA was re-opened two weeks after the beginning of the Second World War as the Central Agency for Prisoners of War, now based on the mandate from the 1929 Geneva Convention. Once again, Étienne Clouzot played a prominent role: 
"in 1939, fuelled by his experience in the International Prisoners of War Agency, he helped organize the Central Prisoners of War Agency, becoming a member of its Technical Directorate"
Another key person became Suzanne Ferrière, who had assisted her uncle Frédéric at the IPWA during WWI and now instituted a new family messaging system.
Already in October 1939, IBM "provided the Agency free of charge with both staff and Watson machines. The latter, thanks to a perforated card system, made it possible to sort and classify information at high speed." Faced with a gigantic growth of personal and institutional data which was handled by some 3,000 staff, the ICRC in 1942 introduced its first filing system. Altogether, the number of index cards rose to about 45 million and the number of transmitted messages to some 120 million, reflecting the new dimensions of human suffering. The ICRC's efforts were awarded in 1944 with its second Nobel Peace Prize after 1917.

One of the last - and most important - documents from the WWII period was issued on 29 August 1945, only days before the end of the war, by Fritz Bilfinger, an ICRC delegate who reached the apocalyptic ruins of Hiroshima just some three weeks after the United States Army Air Forces (USAAF) dropped the atomic bomb "Little Boy" on the Japanese city. His telegram, kept in the archives, recorded a chilling warning of the horrors of the Atomic Age:
“conditions appalling stop city wiped out, eighty percent all hospitals destroyed or seriously damaged; inspected two emergency hospitals, conditions beyond description full stop effect of bomb mysteriously serious stop many victims, apparently recovering, suddenly suffer fatal relapse due to decomposition of white blood cells and other internal injuries, now dying in great numbers stop estimated still over one hundred thousand wounded in emergency hospitals located surroundings, sadly lacking bandaging materials, medicines stop.”
International Committee of the Red Cross archives