Maritime transport, unless as provided for under international maritime agreements, is reserved to vessels flying the national flag, which is granted to vessels in which foreign interests are not greater than 40%.
"Book I
Ships
Title I
General provisions
Art. 1st. Are considered as vessels for the application of this Code, all vessels of at least 25 tons of gauge, which carry out or are intended to carry out usually at sea, the transport of persons or things, fishing, towing or any other browsing operation.
Chapter I: Nationality and registration
Art. 6. A vessel is Congolese which:
1° belongs for more than half, in full ownership or in "bare" ownership, to Congolese;
2° belongs to commercial companies constituted in accordance with Congolese legislation and in which the capital belongs at least for 60 percent either to the State, or to Congolese, or to Congolese companies whose capital belongs at least for 50 percent to Congolese interests.
If the companies referred to in 2° above are capital companies, all the shares must be registered. In companies that own or co-own Congolese vessels, any transfer of shares or units that would have the effect of reducing part of the capital belonging to Congolese, less than the proportion indicated in paragraph 2°.[...]" (Ordinance-Law No. 66-98 – Maritime Navigation Code [google translate])
Ordinance-Law No. 66-98 – Maritime Navigation Code [google translate]
[<a href="https://www.ilo.org/dyn/natlex/docs/SERIAL/84877/95322/F1572507643/COD-84877.pdf">Ordinance</a>]