I just stumbled upon this picture yesterday at Achtung Panzer!
Since 1943, Soviets captured some number of various variants of Panther, which equipped some of their tank units such as Lieutenant Sotnikov’s Guard Company. This unit used captured Panthers as late as spring of 1945, when they had 3 Ausf As, while operating in Prague (Praga) - district of Warsaw. Soviets held Panthers in high regard and considered captured Panther to be a prize. Captured Panthers were then given to successful crews as a kind of reward. In order to keep them running captured German mechanics were pressed into service and in 1944, Panther’s manual was printed in Russian for distribution among tank crews. Captured vehicles temporarily remained in their original colors but with markings of their new owners. Later, some were repainted in dark green and were marked with large tactical markings and white stars for indentification purposes.
“It is suggested to the Red Army to use such German tanks as StuG III and Pz IV due to their relability and availability of spare parts. The new German Panther and Tiger can be used until they broken down without trying to repair them. They have bad engines, transmission and suspension.” - Department of Weaponry of the Red Army, late 1944.
Small number of captured Panthers was also pressed into service by British (e.g. Ausf G “Cuckoo” from 4th Battalion of 6th Coldstream Guards Tank Brigade, North-West Europe, 1944/45[pictured above]), Canadian, French and American units and three were used by the Polish Home Army during the Warsaw Uprising in 1944, against its former owners. Also small number was captured and operated by the French resistance in mid 1944. They took part in fighting in the Rouen area, where two of them were destroyed on August 30th of 1944 by Tigers from sSSPzAbt 102. This was probably the most interesting combat situation involving Panthers.