What is it about Katie Holmes that has professional style watchers breathlessly documenting her every fashion choice?

In the past several days alone, Glamour, Harper’s Bazaar, and InStyle have praised the ways the actress presented herself, with the latter calling one outfit — a nondescript Banana Republic shirtdress worn over a tank top and wide-leg pants — “a master class in elevated basics.” Vogue described a generic-looking slip dress the actress wore in May as “a lazy girl’s shortcut to cool.”

That reliably fawning chorus recently gained another member in A.P.C., the French fashion label founded in the late 1980s on the Gallic ideals of durability and youthfully unstudied chic (think Jane Birkin or Françoise Hardy).

This spring the brand enlisted Ms. Holmes to place her name and her celebrity stamp on a line of sweaters, T-shirts, miniskirts and jeans, some of which are reproductions of items A.P.C. originally sold in the late 1990s and the early 2000s. Prices for the clothes range from about $145 to well over $1,000.

“We like how real she is, that her style is appealing to everyone,” Judith Touitou, the label’s longtime creative director, said of Ms. Holmes. “For a celebrity, she is very sophisticated but also accessible.”

Many have seen Ms. Holmes as the ultimate cool girl since she captivated TV viewers in the late ’90s and the early 2000s as Joey on “Dawson’s Creek,” before her six-year marriage to Tom Cruise catapulted her to another stratosphere of fame.