Is one sinful for employing a committed Muslim maid to work daily without a mahram, knowing that she is already present in the country without a mahram?

It is permissible for a man to hire a free woman or a bondwoman to serve him, provided he adheres to Islamic etiquette, such as not being in seclusion with her, or looking at her private parts or hair. This is permissible as long as no temptation is feared, and the presence of a mahram for the woman is not required except when traveling.