TSLC is a fashion house featured in Grand Theft Auto V.
Its only store is located on the corner of Portola Drive, Carcer Way and Dorset Drive in Rockford Hills, Los Santos. The store occupies a corner site and the window display would indicate it sells women's handbags.
The brand seems likely to be a play on DKNY with the NY obviously being replaced by LC for Liberty City. The TS in TSLC stands for 'Tracee Sharan', as shown on various shirts worn by female pedestrians.