As a foreign national employed or conducting business in DRC, you will typically be subject to:
Personal income tax (Impôt professionnel sur les rémunérations, IPR) on your salaries or fees.
Social security contributions (if enrolled).
Possible municipal or provincial taxes, depending on where you live or work.
Employers usually withhold income tax at source. If you are self-employed or a consultant, you may need to file individual declarations and make periodic payments.