To say that François Beauregard is a master of the simple, cotton-knit shirt is not to denigrate his design skills in any way. Inside his Saint-Laurent boutique, the shirts run from straightforward tanks to dressed-up tees that work equally well with suits or jeans. The fabrics are soft (but durable) and come in a rainbow of colors. Come for the inexpensive shirts, but don’t overlook the rest of his line, which often includes funky, cropped cotton jackets and playful shorts. And don’t even think of comparing him to American Apparel.