The F.T.C. complaint cited another email from a Sunday Riley employee offering tips: “If you notice someone saying things like I didn’t like ‘x’ about it, write a review that says the opposite. The power of reviews is mighty, people look to what others are saying to persuade them and answer potential questions they have.”

Ms. Riley and her company did not respond to email and LinkedIn messages seeking comment for this article. Two public relation firms that previously worked with Sunday Riley said they no longer represented the firm.

Sephora still promotes Sunday Riley products in its stores. The retailer said in an email to The New York Times that it did “not believe the actions at Sunday Riley are representative of our brands or the countless hours our clients have spent sharing their authentic product experiences with us.” The company said it vetted and had removed certain Sunday Riley reviews from its website, particularly if reviews were left the same day the account was created.

Sephora has a new system for verifying the source of reviews and added badges to highlight reviews tied to purchases, the company said. It did not address questions about any punitive action it took against Sunday Riley.

The response from Sephora and the proposed settlement with the F.T.C., which did not include a financial penalty, surprised some in the industry. The commission received roughly 40 comments about the agreement from frustrated consumers, one of whom said it was a “finger wag.”

“It was the most blatant case of fake reviews, and this is how the government responds to it,” said Saoud Khalifah, chief executive of Fakespot, a company that analyzes the authenticity of reviews on sites like Amazon, Sephora and Best Buy. “Now everybody is like, O.K., if that’s the penalty, then why not write more fake reviews and pump ourselves through the roof?”

Two of the F.T.C.’s five commissioners, Rohit Chopra and Rebecca Kelly Slaughter, objected to the proposed settlement. Mr. Chopra said in a statement that it was “unlikely to deter other would-be wrongdoers” and that the agency should impose financial penalties for the growing problem of fake review fraud.