Field help (EMPDED) 

When an employee is granted a specific fixed deduction for business expenses, the deduction rate and the "Fixed" and "Actual" option must be specified. 
In the payroll preparation, if a specific fixed deduction for business expenses is entered, a capped deduction of contribution bases is applied.
if the option is set to "Fixed", the FRAIS_PROF heading is activated. This heading is added to the gross amount and completes the DADS-U 'Amount of business expenses' US41010044 total amount. The amount of the capped deduction is substracted from the gross tax basis (BRUT_FISC heading) and the new amount completes the DAD-U 'Gross tax basis' - S40.G40.00.035.001 total amount.