Dual-current version of SNCF's CC 6500 locomotives, this small series of 4 locomotives registered CC 21001 to CC 21004 are assigned to the Dijon-Perrigny depot to be used mainly on the Paris-Dijon-Vallorbe axis to tow fast and express trains including the Trans-Europ-Express “Cisalpin”. Like the CC 6500 locomotives, they receive the "Grand Confort" livery based on red and gray underlined by an orange strip.

The CC 21003 delivered to the SNCF in 1974, took part in 1977 in a test campaign in the United States of America under the registration X 996 AMTRAK with the specific DC equipment removed. After testing and returning to France, she was returned to type. Faced with competition from the three-current TGV trainsets in Paris-Lausanne and Bern, the 4 CC 21000 locomotives had their equipment dedicated to 25 kV alternating current definitively removed between 1995 and 1996. They were then renumbered CC 6575 to CC 6578 on this occasion. These 4 locomotives were canceled between 2005 and 2007.