Indeed, the fixed amount allocated to these expenses paid by the employer cannot exceed what an official would have received in the same situation. The amounts are updated each year in a regulation of the Government in Council. The day allowance is always 14 EUR and the night allowance 56 EUR for business trips within the Grand Duchy.

As for the allowance for travel abroad, the amounts vary from one country to another. You will find the detailed list in article 2 of the Government in Council Regulation of 2 December 2022:

https://legilux.public.lu/eli/etat/leg/rgc/2022/12/02/a619/jo