Getma International, a unit of the French transport and logistics group NCT Necotrans, won the contract in a 2008 tender against interest from rivals including fellow French port group Bollore and Maersk.
The decree said conventions covering the management, extension and refurbishment of Conakry container port had been annulled "due to a failings by the concessionary regarding its obligations".
NCT Necotrans said in a statement it would examine all means to defend its rights following the damage caused by the annulment of the contract.
The group, which had planned to invest over 100 million euros in the project over 25 years, said Guinean authorities used security forces to stop 400 employees from entering its premises.
As speculation grew last month of a possible move by Guinea to cancel its contract, STCC issued a statement saying Guinea had not launched any procedures set aside for the case that it had not fulfilled its obligations.
That speculation had been triggered by a visit to Conakry by Bollore chief Vincent Bollore last month. Bollore announced plans for a possible investment of $150 million in a separate dry port to ease shipment of goods through the country. (Reuters)
