The Islamic Religious Council of Singapore states: For a salary to be halal, it must fulfill the following conditions:

1. It comes from legitimate jobs. Illegitimate jobs are those that involve haram things, such as alcohol and gambling.

2. The payments received come from one’s own efforts, not those of others.

3. The job does not involve elements of cheating and zhulm (unfairness).

If the commission you receive fulfills the above conditions, then it is halal.