The German sporting goods company and its wholesalers stopped shipments or threatened to halt deliveries of its products to Japanese retailers who cut prices, the anti-trust watchdog said in a statement on its website on Friday.
A spokeswoman for Adidas in Germany said the group was taking the cease-and-desist order seriously.
Compliance with the law is one of the key values for Reebok, she said in a statement, adding Adidas would not have to pay a penalty.
The world's second-largest sporting goods maker after Nike Inc
Adidas shares were down 0.5 percent at 59.75 euros at 0827 GMT, against a flat wider blue-chip index <.GDAXI>.
(Reporting by James Topham, Mayumi Negishi in Tokyo and Christian Kraemer in Munich; Writing by Victoria Bryan; Editing by Ron Popeski and Helen Massy-Beresford)