Discrimination At The Blunt End
Direct discrimination can be obvious: for example, offering different pay scales for men and women. In employment law, it means less favourable treatment causing a detriment to an employee on the grounds of race, sex, disability, sexual orientation, age or religion or belief. In general, the various employment law Acts require that "like must be compared with like" - in other words in order to show less favourable treatment and discrimination there has to be a ‘comparator' (who can be actual or hypothetical) of a different sex, race, etc who has been treated differently.
Direct discrimination is not always obvious to the employer: for example, you may require a woman to attend client meetings with a companion for safety reasons but not a man. If this prevented your female employee getting the same commission or bonus as a male colleague, this would be direct discrimination in an employment law claim.