POW mail was cancelled with an oval , 40:20mm with CENZURAT and different letters.
Colour red or violet.

Further these were often also cancelled with PRISONNIERS DE GUERRE in rectangle 68:10mm
Colour: red, violet or black.

POW mail from hospitals  and mail to the Red Cross were often directed through the Red cross and were cancelled with their cancellation - colour red, rare in black


Civilian post to the Red Cross or to foreign POWs were cancelled with CIVILI (1917-18)

Military prison camps Alexani and Buzau - used on letters from interns

Alexani  30mm, violet  November 1916
Buzau  30mm, violet, May 1917