The High Commission in the UK can provide full details of the code of practice, and can arrange the necessary appointments in Cameroon for an application, and assist with formalities.
Basically the incentives offered include:

The Free Zone regime is available for an enterprise which produces goods and services exclusively for export, or for sale to buyers who reside outside Cameroon.

An enterprise which produces goods and services which will not have deleterious effects on the environment.

Benefits: Streamlined administrative procedures.
Onsite Customer services, and immediate transfer of goods from port.

Commercial benefits:
Exemption from all licenses and quote restrictions.
Potential to sell part of production to local economy.

Tax concessions:
10 year tax holiday on all taxes.
Flat 15% corporate tax in the 11th year.
Profit and loss carry forward during the tax holiday.

Financial Transactions Concessions:
Right to hold foreign exchange accounts in the domestic banking system.
Guaranteed right of transfer aboard of all funds earned and invested in Cameroon.

Trade related concessions:
Exemption from all existing and future import/export duties, taxes and imposts.
Exemption from Import Verification Program, i.e.. S.G.S., Veritas.
Exemption from local sales related taxes.

Labour related concessions:
Right to freely negotiate wages between employer and employees.
Automatic right to work permits for foreign workers, up to 20% of workforce.
Right to replace national social security scheme with a private scheme of equal or better value.

Other benefits:
Right to install own power and telecommunications systems.
Preferential electricity rates, and port charges.
Exemption from price controls.

Trade Unions and Employer Groups in Cameroon.
Both groups operate within the economy. Details can be obtained from the High Commission in the UK