Americans/Brits did it too
The Americans and British also kept Germans as POWs after the war was over, when there was no justification for keeping them imprisoned. The Allies even turned German prisoners over to the Soviets. This violated the laws of the United States of America, the United Kingdom of Great Britain, and several international conventions.
http://en.wikipedia.org/wiki/German_POWs_in_America#After_the_war
http://en.wikipedia.org/wiki/Prisoner_of_war#Treatment_of_POWs_by_the_ Allies
http://en.wikipedia.org/wiki/Forced_labor_of_Germans_after_World_War_I I