Is the amount paid for completing the designs of a public library, which includes 20% for the Ministry's Planning Director, considered unlawful (haram), or if a lump sum is paid without a percentage?

It is not permissible to give an official a bribe or a lump sum in exchange for preferential treatment, as this falls under the category of forbidden gifts to employees. The manager must choose the best and most suitable person for the job without favoritism or demanding a commission.