It comprises a fixed duty and a proportional duty based on the rentable value of the premises used to carry out the taxable activity.

Это предложение из такого контекста:

Companies referred to in Article 206 of the Mayotte General Tax Code which pursue a business or activities on a profit-making basis in Mayotte are liable for corporation tax at a rate of 33.33%.
A trading tax is also payable by all natural and legal persons pursuing a business, industry or
profession.
It comprises a fixed duty and a proportional duty based on the rentable value of the premises used to carry out the taxable activity.
The trading tax for importers is payable by importers of goods and comprises a fixed duty and a
variable tax

Заранее огромное спасибо!