All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
It is not permissible to sell gifts for Christmas as this is helping in and propagating falsehood. Allaah says (interpretation of meaning): {Help you one another in virtue, righteousness and piety but do not help one another in sin and transgression}[5:2]. The matter is even more forbidden and abominable if these gifts contain a wrong belief, like the cross, the picture of a man on the cross and the like, as these are among the gifts that the Christians exchange. If the shop does not sell anything except these kinds of gifts, then it is not permissible to work in this shop. However, if the shop sells goods other than these gifts, then there is no harm in working there on the condition that you do not deal directly with these gifts that are sold or used pertaining to Christmas or other false celebrations.
Allaah knows best.