Number 84 was used for the interrogation of allied SOE agents captured in France (including, for example, Frank Pickersgill, Diana Rowden, and Violette Szabo).

[1] The SD used captured allied wireless sets to transmit bogus coded messages in attempts to flush out resistance groups.

[2] The third floor was used by SS-Standartenführer Helmut Knochen, who was appointed as senior commander of security in Paris in 1940.

The fourth floor was used by SS-Sturmbannführer Josef Kieffer, the commander of number 84, as an office and private quarters.

A senior interrogator at number 84 was Ernest Vogt, a Swiss-German civilian who since 1940 had been attached to the SD as a civil auxiliary in the capacity of translator and interpreter.